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SNAKES , an See also:order (Ophidia) in the class of See also:Reptiles. They may be characterized as very elongated reptiles without limbs (unless with tiny vestiges of posterior limbs), without eyelids and See also:external See also:ear openings, with the See also:teeth anchylosed to the supporting bones, a bifid slender See also:tongue which is telescoped into its basal See also:half, and with a transverse vent. These characters apply to all snakes, although none are See also:peculiar to them. The- ' The curious but apparently well-attested fact of the occurrence in See also:England, near See also:Poole, in See also:June 1851, of a male See also:bird of this See also:species (Zoologist, pp. 3601, 3654) has been overlooked by several writers who profess to mention all cases of a similar See also:character. More detail concerning See also:skull, scales and teeth will be found in the diagnostic descriptions of the various families (vide infra) ; for further anatomical See also:information the reader is referred so the See also:article REPTILES (See also:Anatomy). The snakes are the most highly specialized See also:branch of the Sauna or Squamata, i.e. of scaly reptiles with movable quadrate bones; with a'transverse vent, near the posterior lateral corners of which open the eversible, paired copulatory See also:organs. In the article See also:LIZARD See also:attention is See also:drawn to the many characters which make it difficult, if not impossible, to give diagnoses applicable to all lizards and all snakes. Both these' See also:groups seem" to have reached their See also:climax but recently, while the tortoises, crocodiles and See also:sphenodon are on the descending See also:scale, See also:mere remnants of formerly much more numerous and See also:cosmopolitan' development. The number of See also:recent species of snakes is about s600. The order is practically cosmopolitan, with the exception of New See also:Zealand and certain absolutely isolated oceanic islands, like the Hawaiian islands and the See also:Azores. The N. limit approaches that of the permanently frozen subsoil, going into the See also:arctic circle in Scandinavia, elsewhere sinking to about 54° N.; in the S. hemisphere the 45th parallel may indicate their limit. The number of species and individuals steadily decreases in the cooler temperate zones, whilst it reaches its maximum in the tropics. Every See also:kind of terrain is tenanted, from dense, moist and hot forests at the level of the See also:sea to arid deserts, high plateaus and mountains. In accordance with this See also:general See also:distribution snakes show a See also:great amount of differentiation with regard to their mode of See also:life and general organization; and -from the See also:appearance alone of a snake a ' safe conclusion can be drawn as to its habits. Dr A. See also:Gunther characterizes the See also:chief categories as follows:—(t) Burrowing snakes, which live under ground and but rarely appear on the See also:surface. They have a cylindrical rigid See also:body, covered with generally smooth and polished scales; -a See also:short strong tail; a short rounded or pointed See also:head with narrow mouth; teeth few in number; small or'-rudimentary eyes; no abdominal scutes or only narrow ones. They feed chiefly on invertebrate animals, , and none are poisonous. (2) Ground snakes rarely ascending bushes or entering See also:water. Their body is cylindrical, flexible in every See also:part, covered with smooth or keeled scales, and provided with broad ventral and subcaudal scutes. The non-poisonous kinds of ground snakes are the typical and least specialized snakes, and more, numerous than any of the other kinds. They feed chiefly on terrestrial vertebrates. The See also:majority are non-poisonous; but the, majority of poisonous snakes must be referred to this See also:category. (3) See also:Tree snakes, which are able to climb bushes. or trees with facility or pass even the greater part of, their existence on trees. Their body is generally compressed and slender; their broad ventral scutes are often carinate on the sides. Those kinds which have a less elongate and cylindrical body possess a distinctly prehensile tail. The See also:eye is generally large. Their coloration consists often of See also:bright hues, and sometimes resem)aies that of their surroundings. They feed on animals which likewise' See also:lead an arboreal life, rarely on • eggs. Poisonous as well as innocuous snakes are represented in this category. (4) See also:Freshwater snakes; living in or frequenting fresh See also:waters; they are excellent swimmers and See also:divers. The nostrils are placed on the See also:top of the snout and can be. closed whilst the See also:animal is under water. Their body is covered with small scales and the ventral scutes are mostly narrow; the tail tapering; head See also:flat, rather short; and the eyes of small' See also:size. They feed on See also:fish, frogs and other aquatic animals, and are innocuous and viviparous. (5) Sea snakes are distinguished by the compressed, See also:rudder-shaped tail. They are unable to move on See also:land, feed on fishes, are viviparous and poisonous. The majority of snakes are active during the See also:day, their See also:energy increasing with the increasing temperature; whilst some delight in the moist sweltering See also:heat of dense tropical vegetation, others expose themselves to the fiercest rays of the midday See also:sun. Not a few, however, lead a nocturnal life, and many of them have, accordingly, their See also:pupil contracted into a See also:vertical or more rarely a See also:horizontal slit. Those which inhabit temperate latitudes hibernate. Snakes are the most stationary of all vertebrates; as See also:long as a locality affords them See also:food and shelter they have no inducement to See also:change it. Their dispersal, therefore, must have been extremely slow and See also:gradual. Although able to move with rapidity, they do not keep in See also:motion for any length of See also:time. Their organs of locomotion are the ribs, the number of which is very great, nearly corresponding to that of the vertebrae of the See also:trunk. They can adapt their motions to every variation of the ground over which they move, yet all varieties of snake locomotion are founded on the following See also:simple See also:process. When a part of the body has found some See also:projection of the ground which affords it a point of support, the ribs are drawn more closely together, on alternate sides, thereby producing alternate bends of the body. The hinder portion of the body being drawn after, some part of it (c) finds another support on the rough ground or a projection; and, the anterior bends being stretched in a straight See also:line, the front part of the body is propelled (from a to d) in consequence. During this peculiar locomotion the numerous broad See also:shields of the belly are of great See also:advantage, as by, means of their See also:free edges the snake is enabled to catch and use as points of support the slightest projections of the ground. A pair of ribs corresponds to each of these ventral shields. Snakes are not able to move over a perfectly smooth surface. The conventional See also:representation of the progress of a snake, in which its undulating body is figured as resting by a See also:series of See also:lower bends on the ground whilst the alternate bends are raised above it, is an impossible attitude, nor do snakes ever climb trees in See also:spiral See also:fashion, the classical See also:artistic mode of representation. Also the notion that snakes when attacking are able to jump off the ground is quite erroneous; when they strike an See also:object, they dart the fore part of their body, which was retracted in several bends, forwards in a straight line. And sometimes very active snakes, like the See also:cobra, advance simultaneously with the See also:remainder of the body, which, however, glides in the See also:ordinary fashion over the ground; but no snake is able to impart such an impetus to the whole of its body as to lose its contact with the ground. Some snakes can raise the anterior part of their body and even move in this attitude, but it is only about the anterior See also:fourth or third of the See also:total length which can be thus erected. With very few exceptions, the integuments See also:form imbricate scale-like folds arranged with the greatest regularity; they are small and pluriserial on the upper parts of the body and tail, large and uniserial on the See also:abdomen, and generally biserial on the lower See also:side of the tail. The folds can be stretched out, so that the skin is capable of a great degree of distension. The scales are sometimes rounded behind, but generally rhombic in shape and more or less elongate; they may be quite smooth or provided with a See also:longitudinal See also:ridge or See also:keel in the See also:middle line. The integuments of the head are divided into non-imbricate shields or plates, symmetrically arranged, but not corresponding in size or shape with the underlying See also:cranial bones or having any relation to them. The form and number of the scales and scums, and the shape and arrangement of the head-shields, are of great value in distinguishing the genera and species, and it willtherefore be useful to explain in the accompanying woodcut (fig. 3) the terms by which these parts are designated. The skin does not form eyelids; but the epidermis passes over the eye, forming a transparent disk, See also:concave like the See also:glass of a See also:watch, behind which the eye moves. It is the first part which is See also:cast off when the snake sheds its skin; this is done several times in the See also:year, and the epidermis comes off in a single piece, being, from the mouth towards the tail, turned inside out during the process. The tongue in snakes is narrow, almost See also:worm-like, generally of a See also:black See also:colour and forked, that is, it terminates in front in two extremely See also:fine filaments. It is often exserted with a rapid motion, sometimes with the object of feeling some object, sometimes under the See also:influence of anger or fear. Snakes possess teeth in the maxillaries, mandibles, See also:palatine and pterygoid bones, sometimes also in the intermaxillary; they may be absent in one or the other of the bones mentioned. Deatltlon. In the innocuous snakes the teeth are simple and See also:uniform in structure, thin, See also:sharp like needles, and See also:bent backwards; their See also:function consists merely in seizing and holding the See also:prey. In some all the teeth are nearly of the same size; others possess in front of the jaws (Lycodonts) or behind in the maxillaries (Diacrasterians) a tooth more or less See also:con- n n, - a p r spicuously larger than the See also:rest; whilst others again are distinguished by this larger posterior r tooth being grooved along its See also:outer See also:face. The snakes with this grooved kind of tooth have been named Opisthoglypki, and also Suspecti, because their saliva is more or less poisonous. In the true poisonous snakes the maxillary dentition has undergone a See also:special modification. The so-called colubrine venomous snakes, which retain in a great measure an external resemblance to the innocuous snakes, have the maxillary See also:bone not at all, or but little, shortened, armed in front with a fixed, erect See also:fang,. which is provided with a deep groove or See also:canal FIG. 3.-Head-shields of a Snake for the See also:conveyance of the (Ptyas korros). See also:poison, the fluid being r, Rostral. secreted by a special f, Posterior frontal. poison-gland. One or f', Anterior frontal. more small ordinary teeth v, Vertical. may be placed at some s, Supraciliary or supraocular. distance behind this o, Occipital. poison-fang. In the other n, n', Nasals. venomous snakes (See also:viper- 1, Loreal. Ines and crotalines) the a, Anterior ocular or orbital, or praemaxillary bone is very orbital or anteocular. short, and is armed with p, Postoculars. a single very long curved u, u, Upper labials. fang with a canal and t, t, Temporals. See also:aperture at each end. m, See also:Mental. Although firmly anchy- * *, Lower labials. losed to the bone, the c, c, See also:Chin-shields. tooth, which when at rest is laid backwards, is erectile,—the bone itself being mcbile and rotated See also:round its transverse See also:axis. One or more reserve teeth, in various stages of development, See also:lie between the folds of the See also:gum and are ready to take the See also:place of the one in function whenever it is lost by See also:accident, or See also:shed. The poison is secreted in modified upper labial glands, or in a pair of large glands which are the homologues of the parotid salivary glands of other animals. For a detailed See also:account see See also:West, J. Linn.. See also:Soc. See also:xxv. (1895), p. 419; See also:xxvi. (1898), p. 517; and See also:xxviii. (1900). A duct leads to the furrow or canal of the tooth. The Elapinae have comparatively short fangs, while those of the vipers, especially the crotaline snakes, are much longer, sometimes nearly an See also:inch in length. The Viperidae alone have " erectile " fangs. The mechanism is explained by the diagrams (fig. 4). The poison-bag lies on the side of the head between the eye and the mandibular See also:joint and is held in position by strong ligaments which are attached to this joint and to the maxilla so that the See also:act of opening the jaws and concomitant erection of the fangs automatically squeezes the poison out of the glands. Snakes are carnivorous, and as a See also:rule take living prey only; a few feed habitually or occasionally on eggs. Many See also:swallow their victim alive; others first kill it by smothering it between the coils of their body (constriction). The effects of a bite by a poisonous snake upon a small mammal or bird are almost instantaneous, preventing its See also:escape; and the snake swallows its victim at its leisure, sometimes See also:hours after it has been killed. The prey is always swallowed entire, and, as its. girth generally much exceeds that of the snake, the progress of deglutition is very laborious and slow. Opening their jaws to their fullest extent, they seize the animal generally by the head, and pushing alternately the right and See also:left sides of the jaws forward, they See also:press the body through their elastic gullet into the See also:stomach, its outlines being visible for some time through the distended walls of the abdomen. Digestion is See also:quick and much accelerated by the quantity of saliva which is secreted during the progress of deglutition, and in venomous snakes probably also by the chemical See also:action of the poison. The See also:primary function of the poison-apparatus is to serve as the means of procuring their food, but
From See also:Cambridge Natural See also:History, vol. viii., " See also:Amphibia and Reptiles," by permission of See also:Macmillan & Co., Ltd.
it also serves for See also:defence. Only very few poisonous snakes (like Naja elaps) are known to resent the approach of See also:man so much as to follow him on his See also:retreat and to attack him. Others are much less inclined to avoid collision with man than innocuous kinds. They have thus become one of the greatest scourges to mankind, and See also:Sir J. See also:Fayrer has demonstrated that in See also:India alone annually some 20,000 human beings perish from snake-bites. Therefore it will not be out of place to add here a See also:chapter on snake poison and on the best means (ineffectual though they be in numerous cases) of counteracting its deleterious effects. An excellent account of the nature and of the effect of the venom of snakes, by See also: The following condensed account has been abstracted from it. The poison is a clear, See also:pale-yellow fluid which reacts See also:acid, and contains about 3o%' of solids, but this varies according to the See also:state Snake of concentration. Most venoms are tasteless, but cobra poison. poison is said to be disagreeably See also:bitter. Dried venom keeps indefinitely, and dissolves readily in water. It keeps also in glycerine. It contains albuminous bodies in See also:solution, and is in fact a pure solution of two or more poisonous proteids, which are the active agents, with a small quantity of an organic acid or colouring See also:matter. The venom is destroyed by reagents which precipitate proteids in an insoluble form, or which destroy them, e.g. See also:silver nitrate or permanganate of potash. Hypochlorites have the same effect. But carbolic acid and See also:caustic potash destroy it only after a day or two, consequently they are not a remedy. The venom is generally introduced into the subcutaneous See also:tissue, whence it reaches the general circulation by absorption through the See also:lymph and See also:blood-vessels. When introduced directly into a vein, theeffects are instantaneous. It is absorbed by the conjunctiva, but, excepting cobra poison, not by the mouth or alimentary canal, provided there be no hollow teeth and no abrasions. The venom of the various kinds of snakes acts differently. The Symptoms of Cobra Poison.—Burning See also:pain, followed by sleepiness and weakness in the legs after half an See also:hour. Then profuse salivation, See also:paralysis of the tongue and larynx, and inability to speak. Vomiting, incapacity of See also:movement. The patient seems to be conscious. Breathing becoming difficult. The See also:heart's action is quickened. The pupil remains contracted and reacts to See also:light. At length breathing ceases, with or without See also:convulsions, and the heart slowly stops. Should the patient survive, he returns rapidly to See also:complete See also:health. See also:Rattlesnake Poison.—The painful See also:wound is speedily discoloured and swollen: Constitutional symptoms appear as a rule in less than fifteen minutes: prostration, staggering, See also:cold sweats, vomiting, feeble and quick See also:pulse, See also:dilatation of the pupil, and slight mental disturbance. In this state the patient may See also:die in about twelve hours. If he recovers from the depression, the See also:local symptoms begin to See also:play a much more important part than in cobra-poisoning: great swelling and discoloration extending up the See also:limb and trunk, rise of temperature and repeated See also:syncope, and laboured respiration. See also:Death may occur in this See also:stage. The local haemorrhagic extravasation frequently suppurates, or becomes gangrenous, and from this the patient may die even See also:weeks afterwards. Recovery is sudden, and within a few hours the patient becomes bright and intelligent. Symptoms of Bite from the See also:European Viper.—Local burning pain; the bitten limb soon swells and is discoloured. Great prostration, vomiting and cold, clammy See also:perspiration follow within one to three hours. Pulse very feeble, with slight difficulty in breathing, and restlessness. In severe cases the pulse may become imperceptible, the extremities may become cold, and the patient may pass into See also:coma. In from twelve to twenty-four hours these severe constitutional symptoms usually pass off, but in the meantime the swelling and discoloration have spread enormously. Within a few days recovery usually occurs somewhat suddenly, but death may occur from the severe depression, or from the secondary effects of suppuration. The symptoms of the bite from the Daboia or Vipera russeli resemble the effects of rattlesnake poison, but sanious discharges from the rectum, &c., are an additional and prominent feature. The recovering patient suffers from haemorrhagic extravasations in various organs, besides from the lungs, See also:nose, mouth and bowels. See also:Kidney See also:haemorrhage and See also:albuminuria is a See also:constant symptom. The pupil is always dilated and insensitive to light. Bite of Australian Eta See also:pine Snakes.—Pain and local swelling. The first constitutional symptoms appear in fifteen minutes to two hours. First faintness and irresistible See also:desire to See also:sleep. Then alarming prostration and vomiting. Pulse extremely feeble and See also:thread-Iike, and uncountable. The limbs are cold and the skin is blanched. Respiration becomes shallow with the increasing coma. Sensation is blunted. The pupil is widely dilated and insensible to light. There is sometimes passing of blood. If the patient survives the coma, recovery Is complete and as a rule rapid, without secondary symptoms. The Australian venom and that of all viperine snakes, perhaps also that of the cobra, if introduced rapidly into the circulation, occasions extensive intravascular clotting. If the venom is slowly absorbed, the blood loses its coagulability, owing to the breaking down of the red blood-corpuscles, most so with vipers, less with Australian snakes, least so with the cobra. The cobra venom is supposed to extinguish the functions of the various See also:nerve-centres of the cerebro-See also:spinal system, the paralysation extending from below upwards, and it has a special See also:affinity for the See also:respiratory centre. The toxicity or relative strength of the cobra venom has been calculated to be sixteen times that of the European viper. Snakes can poison each other, even those of the same kind. Treatment.—Apply a ligature above, not on the top of, the situation of the bite, twist the See also:string tightly with a stick. Then make a free incision into the wound. Sucking out is dangerous! Then bandage the limb downwards, progressing towards the wound ; re-See also:peat this several times. Do not keep the ligature longer than half an hour. Then let the circulation return, and apply the ligature again. In any See also:case do not keep the ligature on for more than an hour for fear of See also:gangrene. See also:Direct application into the widened wound of See also:calcium hypochlorite, i.e. See also:bleaching See also:powder, is very See also:good, or of a 1% solution of permanganate of potash, or Condy s fluid. Vigorous cauterization with nitrate of silver, See also:driving the stick into the widened wound, is also good, and it is a remedy which one can carry in the See also:pocket. Quick amputation of the See also:finger is the best remedy of all if a large snake has bitten it. See also:Internal Remedies.—The See also:administration of enormous doses of See also:alcohol is to be condemned strongly. Small, stimulating doses, and repeated, are good, but stimulation can be more effectively produced by See also:ammonia or See also:strychnine. Hypodermic injection of strychnine, in some cases as much as one to two grains (but not into a vein!), has in some cases had good results; but injection of ammonia, instead of doing any good, has disastrous sloughing results. There is only one fairly reliable treatment, that by serum See also:therapeutics, the injection of considerable quantities of serum of animals which have been partially immunized by repeated doses of [that particular] snake-venom. Unfortunately this treatment will not often be avail-able. Several mammals and birds are supposed to be immune by nature against snake-venom. Some more or less immune creatures are the mongoose, the, See also:hedgehog and the See also:pig„ the secretary-bird, the See also:honey See also:buzzard, the See also:stork and probably other snake-eaters. Snakes are oviparous; they See also:deposit from ten to eighty eggs of an See also:ellipsoid shape, covered with a soft leathery See also:shell, in 'places where they are exposed to and hatched by moist heat. The parents ' pay no further attention to them, except the pythons, which incubate their eggs by coiling their body over them, and fiercely defend them. In some families, as many freshwater snakes, the sea snakes, Viperinae. and Crotalinae, the. eggs are retained in the oviduct until the embryo is fully. See also:developed: These snakes bring forth living See also:young.
The See also:classification of snakes has undergone many vicissitudes: J. See also: Stannius (Zoolomie d. Amphib., 1856) made a further improvement by See also:combination of the principles used by his predecessors, and he divided the Angiostomataor narrow-mouthed snakes into Tortricina, Typhlopina and Uropeltacea; the Eurystomnta into Iobola or poisonous, and Asinea or innocuous snakes: Meanwhile J. E. See also: D, See also:Cope (Prot. Ac. Philad.,1864, p. 230) resorted to the modifications of the squamosal,ecto- and endopterygoid bones, the See also:condition of the vestigial limbs, and the teeth: Scolecophidia (Typhlopidae), Catodonta (Glauconiidae), Tortricina (Ilysiidae and Uropeltidae), Asinea, Proteroglypha and Solenoglypha, He adhered to this arrangement in his last comprehensive See also:work (Crocodilians, Lizards and Snakes of See also:North A merica, 1898, Smithsonian Inst., 1900), but combined the Asinea and Proteroglypha as Colubroidea, subdividing these into Peropoda, Aglyphodonta, Glyphodonta, Proteroglypha and Platycerca (Hydrophinae). In his last work he used, with doubtful success, the See also:variations of the penes and the lungs. as additional characters, chiefly for the grouping of the great See also:mass of the Colubroid snakes. G. A. Boulenger (Cat. Snakes, Brit. Mus., 1893-1896) . accepted Cope's principles, and mainly by combining the Asinea of Stannius and Cope with the Proteroglypha as. Colubridae—wherein he was followed by Cope, as mentioned above—and separating therefrom the Peropoda or Boidae, he has produced a logically-conceived system, by far the best hitherto proposed. It is followed in the See also:present article. Boulenger's phylogenetic system stands as follows: Viperidae Uropeltidae C. Opisthoglypha C. Proteroglypha Amblycephalidae Ilysiil ae Xenopeltidae Colubridae Aglypha I I I Typhlopidae Boidae Glauconiidae This means that the Boidae retain most See also:primitive characters. Likewise primitive, but in various respects degraded, mainly owing to burrowing habits, are the Typhlopidae with the Ilysiidae, and Uropeltidae as a terminal branch, and on the other See also:hand the Glauconiidae. The solitary Xenopeltis is in several ways intermediate between Boidae and FIG, 5,--Typhlops bothriorhynchus, from India, natural size. Ilysiidae. The rest of the snakes are supposed to have started from some primitive, non- a horny spine. They are widely distributed in all tropical and sub-degenerate, therefore See also:boa-like See also:group, leading by loss of the tropical countries, even in such solitary places as See also:Christmas See also:Island, vestiges of the See also:hind-limbs and loss of the coronoid bone of the but they do not occur in New Zealand. The chief genus is Typhlops, mandible to the aglyphous or innocuous Colubridae, whence. further differentiation in three new lines has taken place,—(z) the harmless Amblycephalidae as a side-issue, (2) the very poisonous proteroglyphous Elapidae, (3) the moderately or incipiently poisonous Opisthoglypha, out of some of which seem to have arisen the venomous Viperidae. I. No ectopterygoid; pterygoid not extending to quadrate; no supratemporal or squamosal; prefrontal forming a suture with nasal; coronoid present; vestiges of See also:pelvis present. Maxillary vertical, loosely attached, toothed; mandible toothless; a single pair of pelvis bones: Typhlopidae. Maxillary bordering the mouth, forming sutures with the pre-maxillary, prefrontal and frontal, toothless; lower See also:jaw toothed; pubis and ischium present, the latter forming a symphysis: Glauconiidae. II. Ectopterygoid present; upper and lower jaws toothed. A. Coronoid present, prefrontal in contact with nasal. i. Vestiges of hind-limbs; supratemporal present. Squamosal large, suspending the quadrate: Boidae. Squamosal small, intercalated in the cranial See also:wall: Ilysiidae. 2. No vestiges of limbs: squamosal absent: Uropeltidae. B. Coronoid absent; squamosal present. z. Maxillary horizontal; pterygoid reaching quadrate or mandible. Prefrontal in contact with nasal: Xenopeltidae. Prefrontal not in contact with nasal: Colubridae. 2. Maxillary horizontal ; pterygoid not reaching quadrate or mandible: Amblycephalidae. 3. Maxillary vertically erectile, perpendicularly to ectoptery- goid, and reaching quadrate or mandible: Viperidae. For ordinary See also:practical purposes this synopsis is useless, most of the anatomical characters being visible only in the macerated skull. The following characterization of the families is, based upon more accessible features. Eyes vestigial or hidden; lower jaw toothless; without enlarged ventral scales: Typhlopidae. Eyes vestigial; teeth restricted to the lower jaw; without enlarged ventral scales: Glauconiidae. Eyes very small; head not distinct; teeth in the upper and lower jaws; ventral scales scarcely enlarged; tail extremely short, ending obtusely and covered with peculiar scales: Uropeltidae. Eyes functional, free, with vestiges of the hind-limbs appearing as claw-like spurs on each side of the vent. Ventral scales scarcely enlarged: Ilysiidae. Ventral scales transversely enlarged: Boidae. Eyes free; with a pair of poison-fangs in the front part of the mouth, carried by the otherwise toothless, much shortened, and vertically erectile maxillaries; ventral scales transversely enlarged: Viperidae. All the remaining snakes combine the following characters. the maxillaries are typically horizontal, not separately movable, with a series of teeth. The mandible is toothed but has no coronoid bone. There are no vestiges of limbs or of their girdles. The eyes are free. Dentary movably attacned to the tip of the articular bone of the mandible. Skin beautifully iridescent: .Xenopeltidae. Without a mental groove; the ends of the pterygoids are free, not reaching the quadrate-. Head thick and very distinct: Amblycephalidae. With a median longitudinal groove between the shields of the skin: Colubridae. See also:Family 1. TYenLOPIDAE.—Burrowing snakes, mostly small, which have the body covered with smooth, shiny, uniform See also:cycloid scales. The teeth are restricted to the small maxillary bones. The quadrates slant obliquely forward' and are attached directly to the prootics, owing to the See also:absence of squamosals. The prefrontals are in lateral contact with the nasals. The vestiges of the pelvis are reduced to a single bone on each side, and there are no traces of limbs, The eyes are hidden by shields of the skin. The mouth is very narrow, and the halves of the under-jaw are not distensible. About See also:ioo species of these rather archaic snakes are known; in See also:adaptation to their burrowing life and worm and See also:insect See also:diet, they have undergone degradation. The tail is mostly very short and sometimes ends in of which, for instance, T. braminus ranges from See also:southern See also:Asia, the islands of the See also:Indian Ocean and the See also:Malay Islands to southern See also:Africa. Family 2. GLAUCONIIDAE.—Burrowing like the Typhlopidae, which they much resemble externally, but the maxillaries retain their normal position and are toothless, teeth being restricted to the lower jaw, which is short, stout, and not dis- tensible. The pelvic See also:girdle and the hind-limbs show the least reduction found in any recent snakes, ilia, pubes and See also:ischia being still distin- guishable, the last even retaining their sym- physis, and there are small vestiges of the femurs. About 3o species, mostly of the genus Glauconia, in See also:south-western Asia, Africa, See also:Madagascar, the See also:Antilles and both Americas, G. dulcis ranging northwards into See also:Texas, G. humilis into See also:California. Family 3. ILYSIIDAE.—MOStly burrowing. The scales of the long, cylindrical body are smooth and small, scarcely enlarged on the ventral side. The tail is extremely short and See also:blunt. The head is very small and not distinct from the See also:neck, a usual feature in burrowing snakes and lizards. The gape of the mouth is narrow. The quadrate bones are short and stand rather vertically. The squamosals form part of the cranial wall, being firmly wedged in between the quadrate, prootic and occipital bones. Vestiges of the pelvis and hind-limbs are small, but they terminate in claw-like spurs which protrude FIG. 6. Three between the scales on either side of the vent. Views of Head of as in the Boidae. The smali eyes are some-T y p h l o p s bra- times covered by transparent shields. About minus (India)" half-a-dozen species only are known in South magnified. See also:America, See also:Ceylon, the Malay Islands and Indo- See also:China. They are viviparous like the Typhlopidae, upon which they feed besides See also:worms and See also:insects. Ilysia s. Tortsix scytale, one of the " See also:coral-snakes " of tropical South America, is beautiful coral-red with black rings, grows to nearly a yard in length, and is said sometimes to be worn as a necklace by native ladies. Family 4. UROPELTIDAE (RHINOPHIDAE).—Burrowing snakes of Ceylon and southern India, with a very short tail, which ends in a peculiar, often obliquely truncated, See also:shield, hence the name. The eyes are very small. The scales of the body are smooth and are but little larger on the belly. The coloration is mostly beautiful, black and red. The Uropeltidae are in various respects intermediate between the two last and the next family. The quadrates are directly attached to the skull, the squamosals being absent. Teeth are carried in both jaws. There are no vestiges of hind-limbs or of the pelvis. These tail-shielded snakes, of which about 40 species are known, are viviparous and burrow in the ground, preferring See also:damp See also:mountain-forests. Uropeltis grandis, the only species of the type-genus, is confined to Ceylon; about 18 in. in length, it is blackish above, yellow below, often with small spots on the upper and the under surface. Rhino phis sanguineus lives in southern India; it is black above with a bluish See also:gloss, the belly is bright red with black spots, like the See also:convex tail-shield. Family 5. BOIDAE.—Typical, often very large, snakes, which have vestiges of pelvis and hind-limbs, the latter appearing as claw-like spurs on each side of the vent. The scales of the upper surface are usually small and smooth, while those of the belly form one broad series. The quadrate is carried by the horizontally-elongated squamosal, which rests loosely upon the skull. The prefrontals are in contact with the nasals. Sharp, recurved teeth are carried by the mandibles, the pterygoids, palatines, maxillaries, and in the Pythoninae by the premaxillaries also. The Boidae comprise some 6o species, which have been grouped into many See also:fancy genera. The range of the family' extends over all the tropical and subtropical countries, including islands, except New Zealand. Sub-family 1. Pythoninae.—With a pair of supraorbital bones between the prefrontal, frontal and postfrontal bones. The pre-maxilla generally carries a few small teeth. The subcaudal scales are mostly in two rows. The pythons (q.v.) are restricted to the palaeotropical and Australian regions, with the See also:sole exception of Loxocemus bicolor in southern See also:Mexico. Sub-family 2. Boidae.—Without supraorbital bones. The pre-maxilla is toothless. The subcaudal scales form mostly a single See also:row. Widely distributed. Boa (q.v.) in tropical America and with two species in Madagascar. Eunectes murinus, the See also:Anaconda (q.v.), Charina, e.g. bottae, a small See also:sand-snake from See also:Oregon to California. Eryx jaculus, also a sand-snake, from North Africa to Central Asia, and extending into See also:Greece. Enygrus, ranging from New See also:Guinea to the See also:Fiji Islands. Casarca dussumieri, differing from Boa chiefly by the rough and strongly-keeled scales, is confined to Round Island near See also:Mauritius. This makes the occurrence of a species of Corallus in Madagascar less remarkable, while all the others live in Central and South America. Family 6. XENOPEI.TIDAE.—One species, Xenopeltis unicolor, in south-eastern Asia and Malay Islands. Boulenger rightly considers
xxv. 10this snake in various ways intermediate between the Ilysiidae, Boidae and Colubridae. The prefrontal bones are still in contact with the nasals as in the previous families, but the coronoid bones of the mandibles are absent as in the remaining families, and this loss also occurs in the Boine Charina. The most remarkable feature is the dentary bone, which is movably attached to the much-elongated articular bone (cf. Polyodontophis of Colubrinae), the movability being enhanced by the absence of the coronoid. The quadrate is short and thick, and is carried by the broad and short squamosal, which lies flat against the skull, reminding in this respect of Ilysia. The smooth, black and See also: No vestiges of limbs or pelvis. This family comprises about nine-tenths of all recent species of snakes and is cosmopolitan, New Zealand being the most notable exception. The 1300 to 1400 species contain terrestrial, arboreal and aquatic forms, many of which are highly specialized. Boulenger, adopting Dumeril's terms, has divided them into three parallel series: A. Aglypha.—All the teeth are solid, and not grooved. Harmless, non-poisonous. B. Opisthoglypha.—One or more of the posterior maxillary teeth are grooved. Most of these snakes, which number about 300 species, are moderately poisonous. C. Proteroglypha.—The anterior maxillary teeth are grooved or " perforated." About 200 very poisonous species, e.g. cobras, coral-snakes and sea-snakes. The second and third series containing only about 400 species, the Aglypha still present the appalling number of woo species, and even the grouping of this mass into three sub-families does not lighten the task of arranging the See also:chaos, since one of these sub-families contains only one, and the other but a very few species. We have therefore still moo species, all so closely allied that they together are but of sub-family See also:rank. They possess few reliable characters; their modifications are not weighty, and it is almost certain that some of these characters, and even combinations thereof, have been developed independently and in different countries. Many of the so-called genera, or groups of genera, are consequently not to be used either as witnesses of blood-relationship or of See also:geographical distribution. Some of the usual characters employed for systematic purposes, for the making of convenient keys, are the following: The number of rows of scales across the body and in a longitudinal direction; shape and structure of scales,whether smooth or with a longitudinal keel ; arrangement of the shields on the head ; shape of she contracted pupil. Above all, the dentition, which exhibits almost endless modifications, in most cases is difficult to ascertain and to appreciate in its subtle distinctions. Internal, skeletal characters, useless for ordinary practical purposes, are the various apophyses on the ventral side of the vertebrae and the penial armaments fancied by Cope. It is impossible here to mention any but the more obvious genera and groups of colubrine snakes. Series A. AGLYPHA.—Sub-family 1. Acrochordinae—The few genera and species of these ugly-looking snakes are mostly aquatic, inhabiting See also:rivers and estuaries of S.E Asia; but one, Nothopsis, lives on the See also:Isthmus of See also:Darien, and another, Stoliczkaia, is found in the Khasia Hills of N.E. India. Acrochordus javanicus has no enlarged ventral shields; the flat, viperish-looking head is covered with small granules, with the eyes and nostrils well on the upper surface. Chersydrus ranges from See also:Madras to New Guinea; the body and tail are laterally compressed and form a ventral See also:fold which is covered with tiny scales like the rest of the body. The See also:main anatomical See also:justification of this sub-family is given by the postfrontal bones, which, besides bordering the orbits posteriorly, are extended forwards so as to form the upper border of the orbits, separating the latter from the frontals. Sub-family 2. Colubrinae.—The postfrontal bones are restricted to the posterior border of the orbits. The maxillary and dentary bones carry teeth on their whole length. This sub-family contains about See also:I000 species; few of them reach a length of more than two yards, some of the largest belonging to the Indian Zaocys s. Coryphodon,which grow to to ft. Most of them are oviparous. Some are more or less aquatic, others are absolutely arboreal, others again prefer dry, sandy or rocky localities according to their food. The sub-family is cosmopolitan, excepting the New Zealand sub-region, and finds its natural N. limit on the permanently frozen underground, where See also:hibernation is of course impossible. Only a few out of the more than 120 genera can be mentioned here. Coluber in See also:Europe, Asia and North America. C. longissimus s. flavescens s. aesculapii was probably the species held in veneration by the See also:ancient See also:Romans. It grows to a length of 5 ft., climbs extremely well, feeds chiefly on mice, and becomes very tame. Its coloration varies from pale See also:golden brown to black ; the scales are
I1
Coronelline Nymphophidium, the same effect is reached by two prominences at the See also:base of the skull.
Series B. OPISTHOGLYPHA.—One, or a few, of the posterior maxillary teeth have a groove or furrow in front, which conducts the secretion of the enlarged upper labial glands. They are all more or less poisonous, paralysing their prey before, or during the act of swallowing; the poison-fangs See also:standing so far back in the mouth, these snakes cannot easily inflict wounds with them on man; more-over, the poison is not very strong and not available in large quantities. It may well be doubted whether Opisthoglypha form one genuine group instead of a heterogeneous See also:assembly. They comprise about 300 species of terrestrial, arboreal and aquatic forms, and as a group they are almost cosmopolitan, including Madagascar, but excepting new Zealand.
Sub-family i. Dipsadomorphinae.—Nostrils lateral; dentition well developed. Long-tailed, terrestrial and arboreal forms. The tree-snakes are mostly See also:green above with the under parts See also: Coelopeltis, with concave, or grooved scales; C. lacertina s. monspessulanus, one of the largest European snakesinMediterranean countries and south-western Asia. Dipsadomorphus, Dipsas, Leptognathus, Dryophis, Dendrophis and other closely allied genera are typical, very long-bodied and long-tailed tree-snakes, chiefly tropical. The graceful form of their body, the elegance and rapidity of their movements, and the exquisite beauty of their See also:colours have been the admiration of all who have had the good See also:fortune to watch them in their native haunts. The majority lead an exclusively arboreal life; only a few descend to the ground in See also:search of their food. They prey upon every kind of arboreal animal—birds, tree-frogs, tree-lizards, &c. All seem to be diurnal, and the larger kinds attain to a length of about 4 ft. The most beautiful of all snakes are perhaps certain varieties of Chrysopelea ornata, a species extremely See also:common in the Indian See also:Archipelago and many parts of the See also:continent of tropical Asia. One of these varieties is black, with a yellow spot in the centre of each scale; these spots are larger on the back, forming a series of tetrapetalous See also:flowers; the head is similarly ornamented. Another variety has a red back, with pairs of black crossbars, the bands of each pair being separated by a narrow yellow space; sides brown, dotted with black; belly dark green, the outer portion of each ventral shield being yellow, with a blackish spot. The features by which the tree-snakes are distinguished are still more developed in the See also:whip-snakes \\ (Dryophis), whose excessively slender \ body has been compared to the See also:cord of a whip. Although arboreal, like the former, they are nocturnal in their habits, having a horizontal instead of a round pupil of the eye. They are said to be of a fierce dis- position, feeding chiefly on birds. In some of the species the elongate form of the head is still more exaggerated by a pointed flexible appendage of the snout (Passerita), which may be nearly half an inch in length, or See also:leaf-like, as in the Madagascar Langaha. The Mexican Trimorphodon much resemble viperine snakes with the flat, triangular head, narrow neck, slit-like pupil and pugnacious disposition. A still more remarkable resemblance exists in the shape and striking, red, black and yellow coloration between Scolecophis aemulus of See also:Chihuahua and the poisonous Elaps fulvius, the See also:American coral-snake, but Cope has been careful to point out that these two creatures are not known to Sub-family 2. Elachistodonidae. dentaries; some of the vertebrae in the lower region of the neck Represented by Elachistodon westermanni of See also:Bengal, with the same have strongly developed hypapophyses (not provided with a cap of See also:enamel, as has often been asserted), which are directed forwards and See also:pierce the See also:oesophagus. The See also:principal diet of these peculiar snakes seems to consist of eggs. In Cape See also:Colony they are known as " eyervreter, " i.e. See also:egg-eater. A snake, scarcely 20 in. in length, and with a body not thicker than a man's little finger, is able to swallow a See also:hen's egg, a feat which seems quite impossible. As the egg passes at last through the alarmingly distended neck, the snake makes some slight contortions and the swelling collapses, the shell having been filed through by the saw-like apparatus.. Whilst the contents are thus retained without loss, the crumpled shell is then vomited out. This peculiar arrangement occurs also in an Indian snake, Elachiston, which represents, however, a sub-family of the Opisthoglypha. In another, probably also egg-eating snake, the Indian smooth and shiny. Its See also:original See also:home is See also:Italy and S.E. Europe, whence it has spread N. into S. See also:Germany. Its occurrence at widely distant and isolated localities was formerly supposed to be due to its introduction by the Romans. C. See also:corals, from the S. states of N. America far into S. America, reaches 8 ft. in length. C. (Pityophis) sayi, C. eatenifer and others in N. America. Coronella,widely distributed excepting See also:Australia and S. America. C. austriaca s. laevis, the " smooth snake " of Europe, in England, in See also:Hampshire and See also:Dorsetshire, eats chiefly lizards; owing to its coloration, which varies much, it is often mistaken for the viper. C. getula is one of the many N. American species. Zamenis of Europe, Asia, N. Africa, N. ,and Central America, with many species, e.g. Z. mucosus the Indian " See also:rat-snake, " Z. constrictor in the See also:United States. Some species of the Central and S. American genus Urotheca See also:bear an extraordinary resemblance in coloration to the See also:pretty, black, red and yellow poisonous Elaps. Dendrophis of India and Australia (e.g. D. pictus of India), and Leptophis s. Ahaetulla (e.g. L. liocerus, neotropical) may be taken as examples of long and slender tree-snakes. Tropidonotus, with near See also:loo species, is cosmopolitan with the exception of New Zealand. Some of the species, like the Indian T. quincunciatusand T. stolatus and the N. American T. ordinatus, are perhaps more abundant as regards the number of individuals than any other snake. T. natrix, the grass or ringed snake, is very common in Europe, including England but not See also:Scotland or See also:Ireland; easily recognized even at a distance by two yellow or white spots which it has behind its head. It grows rarely to a length of 4 ft.; it never bites, and feeds chiefly on frogs, toads and fishes, but mice are never taken. Its eggs, which are of the size and shape of a See also:dove's egg, are from fifteen to See also:thirty in number, are deposited in See also:mould or under damp leaves, and are glued together into one mass. Polyodontophis of Madagascar, S.E. Asia and Central America is remarkable for having the dentary bones loosely attached to the See also:apex of the elongated articular bone. Calamaria of Indo-China is an example of burrowing snakes, with a short tail and small eyes; in Typhlopophis of the Philippines the eyes are concealed. Sub-family 3. Rhachiodontidae, represented by Dasypeltis scabra of tropical and S. Africa. Characterized by possessing only a few teeth, on the posterior part of the maxillaries, on the palatines and peculiar dentition and with sharp hypapophyses on the vertebrae of the. lower neck, as described of Dasypeltis (see above). Sub-family 3. Homalopsinae.—The nostrils of these absolutely aquatic, viviparous snakes are valvular and placed on the upper surface of the snout. The eyes are small, with vertical pupils. About two dozen ugly-looking species inhabit rivers and estuaries from Bengal to Australia. See also:Cerberus rhynchops; Hypsirhina plumbea, Homalopsis; Hipistes hydrinus of See also:Siam has a compressed body, and much resembles the Hydrophinae in general appearance and its partly marine life. Her peton of See also:Cambodia has a pair of long tentacles on the snout and is said to have a partly See also:vegetable diet! Series C. PROTEROGLYPHA.—The anterior maxillary teeth are deeply grooved, or so folded as to appear hollow or perforated. Behind these enlarged poison-fangs follows a series of smaller, solid teeth, hence the See also:term " proteroglypha," which is intended to mean that the anterior teeth are grooved. These snakes are all very poisonous, mostly viviparous and found in all tropical and sub-tropical countries, with the exception of Madagascar and New Zealand. Sub-family I. Elapinae. Terrestrial, with a cylindrical tail, comprising about 150 species which have been grouped into numerous genera, mostly upon very slight See also:differences. The most remarkable are the following. Naja tripudians and N. haje, the cobra (q.v.). The largest species is the N. bungarus s. elaps, the " hamadryad," " snake-eating cobra," or See also: During such periods of excitement it is even able, by the pressure of the muscles on the poison-duct, to eject the fluid to some distance; hence it shares with the cobra a third Dutch name, that of " spuw See also:slang " (spitting snake). It grows to a length of 2 or 3 ft. Another kind is the "schapsticker" (See also:sheep stinger), S. rhombeatus. It is extremely common in S. Africa, and extends far N. along the E. as well as W. See also:coast. It is of smaller size than the preceding, and causes more injury to animals, such as sheep, See also:dogs, &c. than to man. It varies in colour, but a black See also:mark on the head like an inverted V remains nearly always visible. The species of Bungarus, four in number, are extremely common in India, See also:Burma, and Ceylon, and are distinguished by having only one row of undivided sub-caudal shields. Three of the species have the body ornamented with black rings, but the fourth and most common (B. coeruleus), the krait" of Bengal, possesses a dull and more uniform coloration. The fangs of the bungarums are shorter than those of the cobras, and cannot penetrate so deeply into the wound. Their bite is therefore less dangerous and the effect on the general system slower, so that there is more prospect of recovery by treatment. Nevertheless, the krait is probably the most destructive snake to human life in India, since it is very common and often creeps into the houses. Doliophis intestinalis of Indo-China has enormously developed poison glands, which extend down the whole anterior third of the body, in front of the heart. No part of the See also:world possesses so many snakes of this sub-family as Australia, where, in fact, they replace the non-venomous colubrine snakes; many of them are extremely common and spread over a considerable See also:area. Fortunately the majority are of small size, and their bites are not followed by more severe effects than those from the sting of a hornet. Only the following are dangerous to man and larger animals: the " death-See also:adder," Acanthopis antarcticus, easily recognized by the peculiar end of the tail which is compressed and terminates in a thin horny spine; common throughout Australia to the See also:Moluccas, scarcely one yard in length; the " black snake " (Pseudechis porphyriacus), likewise common throughout the Australian continent, especially in See also:low marshy places, and upwards of 6 ft. in length; it is black, with each scale of the outer series red at the base; when irritated it raises the fore part of its body and flattens out its neck like a cobra, the See also:females are sometimes known as " brown adders "; the " See also:tiger-snake," Notechis scutatus (s. Hoplocephalus curtus), with a similar distribution, and also common in See also:Tasmania, from 5 to 6 ft. long, and considered the most dangerous of the tribe. Good descriptions and figures of all these snakes are given in Krefft's Snakes of Australia (See also:Sydney, 1869, 4to). Several genera of the Elapinae lead a more or less burrowing life; their body is of a uniform cylindrical shape, terminating in a short tail, and covered with short polished scales; their head is short, the mouth rather narrow, and the eye small. They are the tropical American Elaps, the Indian Callophis, the See also:African Poecilophis and the Australian Vermicella. The majority are distinguished by the beautiful arrangement of their bright and highly ornamental colours; many species of Elaps have the See also:pattern of the so-called coral-snakes, their body being encircled by black, red and yellow rings—a pattern r which is peculiar to snakes, venomous as well as non-venomous, of the See also:fauna of tropical America. Although the poison of these narrow-mouthed snakes is probably as virulent as that of the preceding, man has much less to fear from them, as they bite only under great provocation. Moreover, their bite must be frequently without serious effect, owing to their narrow mouth and the small size of their poison-fangs. They are also comparatively of small size, only a few species rarely exceeding a length of 3 ft., for instance Elaps fulvius, which extends into the S. states of N. America. tentaculatum. 292 Sub-family 2. Hydrophinae.—Tail laterally compressed; marine. Of sea-snakes some fifty species are known. All are inhabitants of the tropical Indo-Pacific ocean, and most numerous in and'about the See also:Persian Gulf, in the See also:East Indian Archipelago, and in the seas between S. See also:Japan and N. Australia. One species which is extremely common (Pelamis bicolor), and which is easily recognized by the black colour of its upper and the yellowish tints of its lower parts (both colours being sharply defined), has extended its range W. to the sea round Madagascar, and E. to the Gulf of See also:Panama. One species, however, Distira semperi, is confined to the landlocked freshwater See also:Lake See also:Taal at Luzon in the Philippines. Sea-snakes are viviparous and pass their whole life in the water; they soon die when brought on See also:shore. The scales are very small, often very much reduced, and there are frequently no enlarged ventrals on the compressed belly, but Platurus has broad ventrals. Their motions in the water are almost as rapid as they are uncertain and awkward when the animals are removed out of their proper See also:element. Their nostrils are placed quite at the top of the snout. These openings are small and provided with a See also:valve interiorly, which is opened during respiration, and closed when the animal dives. They have very capacious lungs, extending back- wards to the anus; by retaining See also:air in these extensive lungs they are able to See also:float on the surface of the water and to remain under water for a consider- able length of time. Sea-snakes shed their skin frequently; but it peels off in pieces as in lizards, and not as in the freshwater snakes, in which the integuments come off entire. Several species are remarkable for the extremely slender and prolonged anterior part of the body, and very small head. The eye is small, with round pupil, which is so much contracted by the light when the snake is taken out of the water that the animal becomes blinded and is unable to See also:hit any object it attempts to strike. The tongue is short, and the sheath in which it lies concealed opens near to the front margin of the lower jaw; scarcely more than the two terminating points are exserted from the mouth when the animal is in the water. The mouth shuts in a somewhat different way from that of other snakes: the middle of the rostral shield is produced downwards into a small lobule, which prevents the water from entering the mouth; there is generally a small notch on each side of the lobule for the passage of the two points of the tongue. The food of sea-snakes consists entirely of small fish ; among them species with very strong spines. As all these animals are killed by the poison of the snake before they are swallowed, and as their muscles are perfectly relaxed, their See also:armature is harmless to the snake, which begins to swallow its prey from the head, and de- presses the spines as deglutition proceeds. Sea-snakes belong to the most poisonous Pelamis bicolor. rarely caused by them, because they are extremely shy and swim away on the least alarm; but, when surprised In the submarine cavities forming theirnatural retreats, they will, like any other poisonous terrestrial snake, dart at the disturbing object; and, when out of the water, they See also:attempt to bite every object near them, even turning round to wound their own bodies. They cannot endure captivity, dying in the course of two or three days, even when kept in capacious tanks. The greatest size to which some species attain, according to See also:positive observation, is about 12 ft., and therefore far short of the statements as to the length of the so-called sea-serpents (q.v.). Boulenger has written an interesting account of sea-snakes in Natural See also:Science, i. (t892), p. 44 Seq. Family 8. Amblycephalidae.—The pterygoids are widely separated from the quadrates, not reaching beyond the level of the occipital condyle. This condition can be ascertained without See also:dissection, when the mouth is opened widely. The squamosals are reduced, to See also:pad-like vestiges. Otherwise these snakes agree with the aglyphous Colubridae. Externally they are easily distinguished by the absence of a longitudinal groove on the skin. The head is thick, very distinct from the neck and the pupil is vertical, so that these harmless snakes look rather viperish. About 30 species, with several genera, are known from the See also:oriental and neotropical regions. Amblycephalus, e.g. monticola, with See also:compound body, in S.E. Asia. Family 9. Viperidae.—The maxillaries are very short, movably pivoting upon the prefrontals and also attached to the ectopterygoids, so that they can be erected together with the large poison fangs, which, besides reserve teeth, are the only maxillary teeth. There are also teeth on the palatines, anterior portion of the pterygoids, and on the short dentaries. The short squamosals are very loosely attached to the skull. The prefrontals are not in contact with thenasals. The poison-fangs are " solenoglyphous," perforated, having a wide hole on the anterior side at the base, in connexion with the duct of the large, paired, poison-glands, the presence of which adds considerably to the characteristic broadness of the head. The hole leads into a canal, which opens as a semi-canal towards the end of the tooth. The See also:supply of reserve teeth is indefinite; frequently one or two are lying ready and of equal size to the functional fangs. All the Viperidae are very poisonous and all, except the African Atractaspis, are viviparous. They include terrestrial, semi-aquatic and burrowing types; none of them with any signs of degradation; on the contrary they belong to the most highly organized of snakes. The family is cosmopolitan, excepting Madagascar and the whole of the Australian region. Sub-family 1. Viperinae, vipers (q.v.) or adders.—Without an external See also:pit between eye and nose, and the maxillary bone is not hollowed out above. Absolutely restricted to the Old World, with 9 genera comprising about 40 species. Sub-family 2. Crotalinae.—With a deep cavity or pit on either side between the eye and the nose, lodged in the hollowed-out maxillary bone. The lining of these pits is amply supplied with branches from the trigeminal nerves, but the function is still quite unknown. About 6o species of pit-vipers are recognizable. They can easily be divided into 4 genera: Crotalus and Sistrurus with a rattle at the end of the tail and restricted to America (see RATTLESNAKE) ; secondly, pit-vipers without a rattle: Ancistrodon, with large shields ccvering the upper surface of the head; with about to species, e.g. A. halys in the See also:Caspian See also:district, others in the Himalayas, Ceylon and Sunda islands. Notable American species are the following: A. piscivorus, the " water-viper " from Carolina and See also:Indiana to See also:Florida and Texas. This creature is semi-aquatic and lives chiefly on fishes; it grows to a length of about 5 ft.; the general colour is reddish to dark brown, even blackish, with darker See also:cross-bands or C-shaped markings; a dark, light-edged See also:band extends from the eye to the See also:angle of the mouth. The under parts are yellowish, more or less spotted or quite black. A. contortrix the " See also:moccasin-snake " or " See also:copper-head," so called because of its yellow to See also:pink or pale-brown ground colour, with dark crossbars or triangular marks. The under surface is yellow to reddish, with dark specks. Full-grown specimens arc about t yd. in length. The moccasin-snake ranges fromMassachusetts and See also:Kansas to Florida and Texas and into Mexico, preferring swampy localities or meadows with high grass, where it hunts for small mammals and birds. It is easily distinguished from other North American pit-vipers by the See also:possession of a loreal shield, i.e. a shield intercalated between the two preoculars and the posterior nasal; below the loreal lies the pit. The moccasin and the water-viper have occasionally been mentioned under the name of Trigonocephalus cenchris, one of the many synonyms. Lachesis has the upper surface of the head covered. with very small shields, or with scales, and contains about 4o species, in S. and Central America, the Antilles and also in S.E. Asia. The most See also:ill-famed is L. s. Bothrops s. Craspedocephalus lanceolatus, which inhabits the greater part of S. America, extending into Mexico and the Lower Antilles, notably See also:Martinique, Guadaloupe and See also:Santa See also:Lucia, where it is known as the " Fer de See also:Lance "; Mexicans See also:call it rabo de hueso " or bone-tail, on account of the curiously coloured and spike-like tip of the tail. It is a very quick and highly irascible beast and even known to turn on its pursuer. It grows to a length of 6 ft., lives in swamps, plantations, forests, on the plains and on the hills, and is very prolific, producing dozens of young, which at See also:birth are to in. long and as vicious as their parents. L. s Trimeresurus gramineus s. viridis s. erythurus is one of the See also:Asiatic species, ranging over the whole of India to Hong-See also:kong, See also:Timor and even to the Andaman and Nicobar Islands. It is arboreal, bright green above; the end of the prehensile tail is usually bright red. (H. F. Additional information and CommentsThere are no comments yet for this article.
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