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INSECT , the anglicized See also:form of the See also:Late See also:Lat. insectunt, used by See also:Pliny in his Natural See also:History as the See also:equivalent of the Gr. fvroµov. See also:Aristotle had included in one class " Entoma" the six-legged arthropods which form the See also:modern zoological class of the See also:Hexapoda or Insecta, besides the See also:Arachnida, the centipedes and the millipedes. The word was introduced to See also:English readers in a See also:translation (16or) of Pliny's Natural History by See also:Philemon See also: H. C.) nearly all cases these creatures are nocturnal, and the See also:majority are terrestrial, many burrowing in the ground, although a few are arboreal and others aquatic. They have plantigrade or partially plantigrade feet, that is to say, they apply the whole or the greater portion of the soles to the ground when walking; and there are generally five toes, each terminating in a claw, and the first never being opposable to the others in either the fore or See also:hind See also:limb. A full See also:series of differentiated See also:teeth, including temporary or See also:deciduous See also:milk-molars, is See also:developed, and the cheek-teeth have distinct roots and are crowned with See also:sharp cusps, which in some instances are three in number and arranged in a triangle. Very frequently the number of the teeth is the typical See also:forty-four, arranged as i. 3i c. i, p. , in. 3, but occasionally there is a See also:fourth pair of molars, while the incisors may be reduced to functionaries, mostly of the 5th and 6th centuries. Since See also:Gori's I two pairs above and one below, and the canine is frequently well-known See also:work on this class of monuments (See also:Thesaurus veterum' like an incisor or a premolar. The See also:skull is of a See also:primitive type, diptychorum, &c., 3 vols., See also:Florence, 1759) no comprehensive collection often with vacuities on the See also:palate, as in marsupials, with a of them has been published, but a full See also:list is given by H de Villefosse See also:mina exposed. The uterus is two-horned; the See also:placenta, so far as known, is deciduate and discoidal; the testes are abdominal or inguinal; and the teats usually numerous. The See also:body in several instances is covered with sharp spines in See also:place of See also:hair. The See also:great majority of the Insectivora are nocturnal in their habits, and their whole structure indicates an extremely See also:low grade of organisation, fully as low as that of marsupials. It is noteworthy that the dentition in several of the groups approximates to that of the See also:extinct mammals of the See also:Jurassic See also:epoch (see See also:MARSUPIALIA), and exhibits more or less distinctly the primitive tritubercular type. Although the past history of the See also:group is very imperfectly known, it seems probable that the Insectivora are nearly related to the See also:original primitive mammalian stock. Indeed, it has been stated that were it not for the apparently advanced type of placenta, they might easily be regarded as the little modified descendants of the ancestors of most other mammals. Probably they are in some way related to the creodont carnivores (see See also:CREODONTA), but if, as has been suggested, the latter are akin to the primitive ungulates, the connexion would seem to be less See also:close than has been sometimes supposed. Representatives of this See also:order are found throughout the temperate and tropical parts of both hemispheres, with the exception of See also:South See also:America (where only a few shrews have effected an entrance from the See also:north) and See also:Australia, and exhibit much variety both in organization and in See also:habit. The greater number are See also:cursorial, but some (Talpa, Chrysochloris, Oryzorictes) are burrowing, others (Limnogale, Potamogale, Nectogale, Myogale) aquatic, and some (Tupaiidae) arboreal. To the great majority the See also:term insectivorous is applicable, although Potamogale is said to feed on See also:fish, and the moles live chiefly on worms. Not-withstanding the nature of their See also:food, much variety prevails in the form and number of the teeth, and while in many cases the division into incisors, canines, premolars and molars may be readily traced, in others, forming the great majority of the See also:species, such as the shrews, this is difficult. In most cases the See also:brain-cavity is of small relative capacity, and in no instance is the brain-See also:case elevated to any considerable extent above the See also:face-See also:line. The facial See also:part of the skull is generally much produced, and the premaxillary and nasal bones well developed; but the cheek, or zygomatic See also:arch, is usually slender or deficient, the latter being the case in most of the species, and See also:post-orbital processes of the frontals are found only in the Tupaiidae and Macroscelididae. The number of dorsal vertebrae varies from 1.3 in Tupaia to In in C'entries, of lumbar from 3 in Chrysochloris to 6 in Talpa and Sore.r, and of caudal from the rudimentary vertebrae of Centetes to the 40 or more well-developed ones of Microgale. The See also:breast-See also:bone, or sternum, is variable, but generally narrow, bilobate in front and divided into segments. The See also:shoulder-See also:girdle presents extreme adaptive modifications in the See also:mole, in relation to the use of the fore-limbs in burrowing; but in the See also:golden moles the fore-See also:arm and fore-See also:foot alone become specially modified. In Macroscelides the bones of the fore-arm are See also:united at their See also:lower ends, but in all other Insectivora the See also:radius and ulna are distinct. The fore-foot has generally five digits; but in Rhynchocyon and in one species of Oryzoricies the first toe is absent, and in the moles it is extremely modified. The femur has, in most species, a prominent See also:ridge below the greater trochanter presenting the characters of a third trochanter. In Tupaia, Centetes, Hemicentetes, Ericulus and Solenodon the See also:tibia and fibula are distinct, but in most other genera united. The hind-foot consists usually of five digits (rarely four by reduction of the first), and in some, as in the leaping species (Macroscelides, Rhynchocyon), the tarsal bones are elongated. The form of the See also:pelvis, and especially of the symphysis pubis, varies within certain limits, so that while in the Tupaiidae and Macroscelididae there is a See also:long symphysis, in the Erinaceidae, Centetidae and Potamogalidae it is See also:short, and in the Soricidae, Talpidae and Chrysochloridae there is none. Owing to the similarity in the See also:character of the food, the truly insectivorous species, forming more than nine-tenths of the order, See also:present little variety in the structure of the See also:digestive See also:organs. The See also:stomach is a See also:simple, thin-walled See also:sac; sometimes as in Centetes, with the pyloric and oesophageal openings close together; the intestinal See also:canal has much the same calibre throughout, and varies from three (in the shrews) to twelve times (in the hedgehogs) the length of the See also:head and body. In the arboreal Tupaia and the allied Macroscelididae, which probably feed on vegetanle substances as well as insects most of the species possess a caecum. The See also:liver is deeply divided into lobes; the right and See also:left lateral being cut off by deep fissures; both the caudate and Spigelian lobes are generally well developed, and the See also:gall-See also:bladder, usually large and globular, is placed on the See also:middle of the posterior See also:surface of the right central See also:lobe. All the members of the order appear to be highly prolific, the number of See also:young varying from two to eight in the See also:hedgehog, and from twelve to twenty-one in the See also:tenrec. The position of the milk-glands and the number of teats vary greatly. In Solenodon there is a single pair of post-inguinal teats, but in most species these organs range from the See also:thorax to the See also:abdomen, varying from two pairs in Gymnura to twelve in the tenrec. In the golden moles the thoracic and inguinal teats are lodged in deep cut-shaped depressions. See also:Scent-glands exist in many species. In most shrews they occur on the sides of the body at a short distance behind the axilla, and their exudation is probably protective, as few carnivorous animals will eat their dead bodies. In both species of Gymnura and in Potantogale large pouches are situated on each See also:side of the rectum, and See also:discharge their secretions by ducts, opening in the first-named genus in front of and in the latter within the margin of the vent. In the tenrec similarly situated glands discharge by pores opening at the bottom of deep pits. The skin is thin, but in many species lined with well-developed muscles, which are probably more developed in hedgehogs than in any other mammals. In this See also:family and in the tenrec most of the species are protected by spines implanted in the skin-muscle, or panniculus carnosus. The Insectivora may be divided into two groups, according to the degree of development of the See also:union between the two halves of the See also:Tree- pelvis. The first group is characterized by the full Shrews. development of this union,. both pubis' and ischium entering into the symphysis. The tympanum remains as a See also:ring within an auditory bulla; the See also:orbit is either surrounded by bone, or separated from the hinder part of the skull by 'a post-orbital See also:process of the frontal; the upper molars have broad 5-cusped crowns with a W-shaped See also:pattern; and the See also:intestine is generally furnished with a caecum. The first family of this group is the Tupaiidae, represented by the tree-shrews, or tupaias, of the Indo-See also:Malay countries, characterized by the See also:complete bony ring See also:round theeye-socket, the freedom of the fibula from the tibia in the hind-limb, and the See also:absence of any marked See also:elongation of the See also:tarsus. The dental See also:formula is i. , c. }, p. m. f, See also:total 38. In See also:appearance and habits tree-shrews are extremely like squirrels, although they differ, of course, in tote as regards their dentition. A large number of species are included as the typical genus Tupaia, which ranges from north-eastern See also:India to the great Malay Islands. In these animals the tail has a fringe of long hairs on opposite sides throughout its length. In the See also:pen-tailed tree-See also:shrew (Ptilocercus lowii), fig. I, the only representative of its genus, and a native of See also:Sumatra, See also:Borneo and the Malay See also:Peninsula, the fringes of long hair are confined to the terminal third of the tail. There are also See also:differences in the skulls of the two genera. A third genus, Urogale, represented by U. cylindrura of the mountains of Mindanao, in the Philippines, and U. everetti, of Borneo, has been established for the round-tailed tupaias, in which the tail is uniformly short-haired, and the second upper incisor and the lower canines are unusually large, the third lower incisor being proportionately small, and also erect, while the second upper incisor resembles acanine. (See TREE-SHREW.) In See also:Africa the tupaias are apparently represented by the See also:jumping-shrews, or See also:elephant-shrews (so called from their elongated muzzles), constituting the family Macroscelididae. From the Tupaiidae the members of this family are readily distinguished by the fact that the socket of the See also:eye, in place of having a complete bony ring, is separated from the hinder part of the skull merely by a post-orbital process of the frontal bone, and also by the more or less marked elongation of the tarsus or lower portion of the hind-limb; another feature being the union of the lower ends of the tibia and fibula. As indicated by one of their names, the members of the group leap after the See also:fashion of gerbils, or jerboas, and hence walk much more on their toes than the majority of the order. In the typical genus Macroscelides, which ranges all over Africa and has numerous specific representa- tives, the dental formula is i. , c.+, p. 1, m. 2 or 3, total 40 or 42; while there are five toes to each foot, and the lower ends of the radius and ulna are united. In Petrodromus (fig. 2) of See also:East Africa, there are only four front-toes, and the hairs on the lower part of the tail form stiff bristles, with swollen tips; the dental formula being the same as that of those species of Macroscelides as have only two lower molars. A further reduction of the number of the digits takes place in the long-nosed jumping-shrews of the genus Rhynchocyon, Mich are larger animals with a much longer snout, only four toes to each foot, and a dental formula of i. I See also:oar o, c. p. +, m. , total 36 or 34.
Some of the species, all of which are East See also:African, differ from the members of the typical genus by the deep rufous See also: , c. I I or o' p. , q, or m. . There are about a dozen species, all confined to the Old See also:World. The variation in the dental formula of some of the best known of these is as follows: i. c. , p. m. 2 X2 (T. wogura, robusta). i. , c. 1, p. 1, nz X2 (1'. europaea, caeca, See also:romana, longirostris, micrura). i. c. p. m. 1X2 (T. leucura leptura). i. c. p. R, m. X2 (T. moschata). Except in T. europaea, the eyes are covered by a membrane. In T. micrura the short tail is concealed by the fur. T. europaea extends from See also:England to See also:Japan. T. caeca and T. romana are found south of the See also:Alps, the remaining species are all See also:Asiatic, two only--T. micrura and T. leucuraoccurring south of the See also:Himalaya. The genus may be split up into subgenera corresponding with the above table; these subdivisions being sometimes accorded full - generic See also:rank. For instance the See also:Japanese T. wogura and the Siberian T. robusta are often referred to under the See also:ill-See also:sounding titles of Mogera wogura and M. robusta. Referring more fully to the See also:European species, it may be mentioned that the mole exhibits in its organization perfect See also:adaptation to its mode of See also:life. In the structure of the See also:skeleton striking departures from the typical mammalian forms are noticeable. The first sternal bone is so much produced as to extend forward as far as a vertical line from the second cervical vertebra, carrying with it the very short almost quadrate clavicles, which are articulated with its anterior extremity and externally with the humeri, being also connected ligamentously with the scapula. The fore-limbs are thus brought opposite the sides of the See also:neck, and from this position a threefold See also:advantage is derived:—in the first place, as this is the narrowest part of the body, they add little to the width, which, if increased, would lessen the See also:power of See also:movement in a confined space; secondly this position allows of a longer fore-limb than would otherwise bepossible, and so increases its See also:lever power; and, thirdly, although the entire limb is relatively short, its anterior position enables the animal, when burrowing, to thrust the claws so far forward as to be in a line with the end of the muzzle, the importance of which is evident. Posteriorly, we find the hind-limbs removed out of the way by approximation of the See also:hip-See also:joints to the centre line of the body. This is effected by inward curvature of the innominate bones at the See also:acetabulum to such an extent that they almost meet in the centre, while the pubic bones are widely separated behind. The shortness of the fore-limb is due to the humerus, which, like the clavicle, is so reduced in length as to present the appearance of a flattened x-shaped bone, with prominent ridges and deep depressions for the attachments of powerful muscles. Its upper extremity presents two rounded prominences; the smaller, the true head of the bone, articulates as usual with the scapula; the larger, which is the See also:external tuberosity rounded off, forms a See also:separate See also:joint with the end of the clavicle. This See also:double See also:articulation gives the rigidity necessary to sup-See also:port the great lateral presure sustained by the fore-limb in excavating. The bones of the fore-See also:leg are normal, but those of the fore-foot are flattened and laterally See also:expanded. FIG. 3.—Skeleton of Mole (Talpa The great width of the europaea) (lower See also:jaw removed to show fore-foot is also partly due See also:base of skull). to the presence of a See also:peculiar c, Calcaneum. bone on the inner side of c.h, Clavicular articulation of the the See also:palm and articulating humerus. with the See also:wrist. cl, Clavicle. The muscles acting on e.c, External condyle of humerus. these modified limbs are f, Femur. homologous with those of fb, Fibula. cursorial insectivora,differ- fc, Falciform bone (radial sesamoid). ing only in their relative h, Humerus. development. The tendon i.c, See also:Internal condyle of humerus. of the biceps traverses a il, Left iliac bone. long bony See also:tunnel, formed i.p, See also:Ramus of the ilium and pubis. by the expansion of the is, Ischium. margin of the bicipital l.d, Ridge of insertion of latissimu: groove for the insertion dorsi muscle. of the See also:pectoralis See also:major l.t, Lesser trochanter. muscle; the anterior m, Manubrium sterni. division of the latter o, Fourth hypapophysial sesamoid muscle is unconnected with ossicle. the sternum, extending ol, Olecranon. across as a See also:band between p, Pubic bone widely separated the humeri, and co-ordi- from that of the opposite side. nating the motions of the pa, Patella. fore-limbs. The teres major P.m, Ridge for insertion of pectoralis and latissimus dorsi major muscle. muscles are of immense pt, Pectineal See also:eminence. size, inserted into the r, Radius. prominent ridge below the rb, First See also:rib. See also:pectoral See also:attachment, and s, Plantar sesamoid ossicle corre- are the See also:principal agents in sponding to the radial sesamoid the excavating See also:action of (os falciform) in the manus. the limb. The cervical sc, Scapula. muscles connecting the s.h, Scapular articulation of the slender scapulae, and humerus. through them the fore- t, Tibia. limbs,with the centre line of u, Ulna. the neck and with the occi- put are large, and the ligamentum nuchae between them is ossified. The latter condition appears to be due to the prolongation forwards of the sternum, preventing flexion of the head downwards ; and accordingly, the normal See also:office of the See also:ligament being lost, it ossifies, and affords a fixed point for the origins of the superficial cervical beyond the margin of the upper See also:lip; the toes are webbed as far as muscles. the bases of the claws; and the long scaly tail is laterally flattened. The skull is long, with slender zygomatic See also:arches; the nasal bones forming a powerful See also:instrument of propulsion when See also:swimming. This are strong and See also:early become united, and in front of them the nostrils species inhabits the See also:banks of streams and lakes in south-east See also:Russia, are continued forwards in tubes formed of thick See also:cartilage, the septum where its food consists of various aquatic insects. M. pyrenaica, between which becomes partially or wholly ossified beneath. There living in a similar manner in the See also:Pyrenees, is much smaller, has a are 7 cervical, 13 dorsal, 6 lumbar, 6 sacral and so-12 caudal verte- cylindrical tail, and a relatively long snout. brae; of the dorsal and lumbar there may be one more or less. The Shrew-mice, or, shortly, shrews (Soruidae), are closely related The sacral vertebrae are united by their expanded and compressed to the Talpidae, with which they are connected by means of some spinous processes, and all the others, with the exception of the of the subfamily Myogalinae. They are, however, dis- Shrews. cervical, are closely and solidly articulated together, so as to support tinguished by the ring-like tympanic, the incompleteness the powerful propulsive and fossorial actions of the limbs. The of the zygomatic arch, the tubercular-sectorial type of upper molar, upper incisors are simple See also:chisel-edged teeth; the canine is long and the two-cusped first upper incisor, and the forward direction of the two-rooted; then follow three subequal conical premolars, and a corresponding lower tooth. As a See also:rule they are terrestrial, but a few fourth, much larger, and like a canine; these are succeeded by three are aquatic. molars with W-shaped cusps. In the lower jaw the three incisors on The dentition (fig. 5) is characteristic, and affords one of the See also:chief each side are slightly smaller, and slant more forwards; close behind means of classifying this exceedingly difficult group of mammals. them is a tooth which, though like them, must, from its position in There are no lower canines, and front of the upper canine, be considered as the canine; behind it, always six functional teeth on each but but separated by an See also:interval, is a large double-rooted conical tooth, side of the lower jaw, but in some i the first premolar; the three following premolars are like the corre- rare instances an additional rudi- i sponding teeth above, but smaller, and are succeeded, as above, by mentary tooth is squeezed in be-the three molars. See MOLE. tween two of the others. The first In the other members of the Talpinae, which are North See also:American, pair of teeth in each jaw differ from the first upper incisor is much taller than the second. They include the See also:rest; in the upper jaw they the curious star-nosed mole (Condylura cristata) , which has the typical are hooked and have a more or series of 44 teeth and a series of fleshy appendages round the ex- less pronounced basal See also:cusp; in the trecnity of the snout; the species known as Scapanus townsendi lower jaw they are long and See also:pro- I, p ject horizontally forwards, some- . ej ~ times with an upward See also:curve at (I ji _ I f the tip. Behind the first upper incisor comes a variable number of small teeth, of which, when all L c p' as' are developed, the first two are in- FIG. 5.-Skull "and Dentition cisors, the third the canine, and of a Shrew-See also:mouse (Sorex-veraethe next two premolars; behind pads); i, first incisors; c in these, again, are four larger teeth, of the upper jaw is the canine; which the front one is the last and p-m the three premolars, premolar, while the other three are behind which are the three molars. Thus we have in the molars; in the lower jaw c is typical genus Sorex(fig. 5) the dental the second incisor, and p the formula i. c. p. m. i, total single premolar. 32, or twenty upper and twelve lower teeth. The lower formula, as already stated, is See also:constant, but the number of the upper series varies from the above maximum of twenty to a minimum of fourteen in Diplomesodon and Anurosorex, in which the formula is i. 2, c. I, P. I, M. 3. From the relation of the fourth upper tooth to the premaxillo-maxillary suture it has been supposed that shrews, like many polyprotodont marsupials, have four pairs of upper incisors; but this is improbable, and the formula is accordingly here taken to follow the ordinary placental type.
Shrews may be divided into two sections, according as to whether the teeth are tipped with brownish or reddish or are wholly See also: The relative proportions of the first and second upper former in the absence of well-defined fringes to the digits, but agree-incisors are also as in Talpa, but there are only two pairs of lower ing with it closely in dentition, in the large size of the infra-orbital incisors. foramen, and in the remarkable shortness of the angular process Among the more typical Myogalinae, mention may be made of of the lower jaw. In India and See also:Burma the place of Sorex is taken Dymecodon pilirostris, from Japan, representing a genus by itself; by Soriculus, in which the upper teeth are generally 18, although nearly allied to which are the shrew-moles, as represented by the rarely 20, and the generative organs have an opening in See also:common with small and long-tailed Urotrichus of Japan, with incisors and pre- the vent after the fashion of the monotreme mammals. The latter molars 3, and U. (Neurotrichus) gibbsi of North America, in which feature occurs in the North American Blarina, which is characterized the premolars are J;. A still more interesting form is the Tibetan I by the truncation of the upper part of the See also:ear and the short tail, the Uropsilus soricipes, a non-burrowing species, with the external number of upper teeth being 20 or 18. Another American genus, appearance of a shrew combined with the skull of a mole, the feet Notiosorex, in which the ear is well developed and the tail See also:medium, being much narrower than in Urotrichus, and the dental formula has only 16 upper teeth. From all the rest of the red-toothed group i. I. c. ;, p. i, m. the See also:water-shrew, Neomys (or Crossopus) fodiens, of Europe and The typical representatives of the subfamily are the two European See also:northern Asia, differs by the fringe of long hairs on the lower surface desmans, Myogale moschata and M. pyrenaica, which are aquatic in of the tail; the number of upper teeth being 18. habits and have the feet webbed and the full series of 44 teeth. In the white-toothed, or crocidurine, group, the small African genus The former is by far the largest member of the whole family, its total Myosorex, which has either 18 or 20 upper teeth, includes long-length being about 16 in. Its long See also:proboscis-like snout projects far tailed and large-eared species in which the aperture of the generative organs and the vent, although close together, are yet distinct. In the See also:musk-shrews (Crocidura), on the other See also:hand, which are common to Europe, Asia and Africa, the reproductive organs and the alimentary canal discharge into a common See also:cloaca, the long tail is sparsely covered with long and short hairs, there are anal glands secreting a strong musky fluid, and the number of upper teeth is 16 or 18. Diplomesodon pukhellus of the See also:Kirghiz See also:steppes, has, on the other hand, only 14 upper teeth, and is further characterized by the moderately long tail and the hairy soles of the hind-feet. Another genus is represented by the Tibetan Anurosorex squamipes, which has the same dental formula, but a mole-like form, rudimentary tail and scaly hind-soles. Lastly, we have two Asiatic See also:mountain aquatic sppeecies, Chimarrogale hsmalayaca of the Himalayas and Nectogale elegans of See also:Tibet, which have fringed tails like the European water-shrew, and i6 upper teeth, the former characterized by the small but perfect external ears, and the latter (fig. 6) by the absence of the ears and presence of adhesive disks on the feet. It will be seen that the red- and the white-toothed series have parallel representative forms, which may indicate that the division of the family into the two groups is one based rather on convenience than on essential differences. See SHREW. From the shrews, the hedgehogs and gymnuras, or See also:rat-shrews, collectively forming the family Erinaceidae, differ structurally by the broader ring made by the tympanic, the complete zygomatic arch, the five-cusped broad upper molars, and the presence of a short pubic symphysis. At the present See also:day they are an exclusively Old World group. The typical group, or Erinaceinae, is represented only by the hedgehogs, with the one genus Erinaceus, easily recognized by their spiny coats, and further characterized by the rudimentary Hedge- tail, the presence of vacuities in the palate, and the broad hogs. pelvis. Hedgehogs (Erinaceus) have the dental formula i. j, c. p. 1, m. 1, and are represented by over a See also:score of species, distributed throughout Europe, Africa and the greater part of Asia, but unknown in See also:Madagascar, See also:Ceylon, Burma, See also:Siam, the Malay countries, and, of course, Australia. All the species resemble one another in the See also:armour of spines covering the upper surface and sides of the body; and all possess the power of See also:rolling themselves up into the form of a See also:ball protected on all sides by these spines, the skin of the back being brought downwards and inwards over the head and tail so as to include the limbs by the action of special muscles. Curiously enough the European hedgehog (E. europaeus) is the most aberrant species, differing from all the rest in the peculiarly-shaped and single-rooted third upper incisor. and first premolar (fig. 7, A), and in its very coarse harsh fur. The dentition of the long-eared See also:Indian E. grayi (fig. 7, B) may, on the other hand, be considered characteristic of all the other species, the only important differences being found in the variable size and position of the second upper Premolar, which is very small, external and deciduous in the Indian E. micro pus and E. ptctus. The former species, limited to South India, is further distinguished by the absence of the jugal bone. Of African species, E. diadematus, with long frontal spines, is probably the commonest, and E. albiventris has been made the type of a separate genus on account of the total absence of the first front-toe. See HEDGEHOG. The members of the second subfamily, Gymnurinae, are more or less rat-like animals, confined to the Malay countries, and easily Rte- distinguished from the hedgehogs by the absence of spines among the fur and the well-developed tail. They also lack shrew. vacuities in the palate, and have a long and narrow pelvis. The typical representative of the family is the greater rat-shrew, at greater gymnura (Gymnura rafflesi) a creature which may be compared to a See also:giant shrew, and whose colour is partly See also:black and partly white, although a uniformly See also:pale-coloured race. (G. r. See also:alba) inhabits Borneo. In common with the next genus, it has the full series of 44 teeth; and its range extends from See also:Tenasserim and the Malay Peninsula to Sumatra and Borneo, the See also:island individuals being stated to be considerably larger than those from the mainland. In this species the length of the tail is about three-fourths that of the head and body; but in the lesser rat-shrew (Hylomys suillus), ranging from Burma and the Malay Peninsula to See also:Java and Sumatra, the former See also:dimension is only about one-See also:sixth of the latter. In the Philippines the group is represented by Podogymnura truei, distinguished from the other genera by the great elongation of the hind-foot, the tail being likewise long. There are only three pairs of pre-molars in each jaw. In the remaining families of the Insectivora the tibia and fibula may be either separated or united at the lower end; there is no descent of the testes, except in Solenodon; a short symphysis is formed by the junction of the pubic epi- /nsectt- physes; and the upper molars are generally small, and vorons triangular, with three cusps arranged in a V. The first See also:Otter. family, Potamogalidae, is represented by the otter-like Potamogale velox of the See also:rivers of See also:West Africa (fig. 8), distinguished from all other members of the order by the absence of clavicles. The tibia and fibula are unitea inferiorly, the skull has a ring-like tympanic, no zygomatic arch, and the vpper molars are of the tuberculo-sectorial type, with broader crowns than in the following families. The dental formula is i. 3, c. }, p. f, in. 3, total 40. This animal inhabits the banks of streams in west See also:equatorial Africa, and its whole structure indicates an aquatic life. It is nearly 2 ft. in length, the tail measuring about See also:half. The long cylindrical body is continued uninterruptedly into the thick laterally compressed tail, the legs are very short, and the toes are not webbed, progression through the water depending wholly on the action of the powerful tail, while the limbs are folded inwards and backwards. The muzzle is broad and fiat. and the nostrils are protected by valves, The fur is dark brown the same as in Oryzorictes. Finally, Limnogale mergulus, a creature about the size of a black rat, has webbed toes and a laterally come pressed tail, evidently adapted for swimming. See TENREC. All the foregoing are natives of Madagascar. It has been suggested , however, that two remarkable West Indian insectivores, namely Solenodon cubanus of See also:Cuba (fig. II) and S. paradoxus of Hayti, should be regarded as representing merely a sub-family of Centetidae. It is true that the See also:main features distinguishing these See also:strange creatures from the Malagasy repre sentatives of that family are the constriction of the skull behind the. Selena See also:don. above, the extremities of the hairs on the back being of a metallic See also:violet See also:hue by reflected See also:light, beneath whitish. In the remaining groups the upper molars form narrow V's of the true tritubercular type. The family, Centetidae, represented by the Tenrec, tenrec and a number of allied animals from Madagascar, is specially characterized by the ring-like tympanic, and the absence of a zygomatic arch and of any constriction of the skull behind the orbits, and the presence of teats on the breast as well as the abdomen. In the more typical members of the family the tibia and fibula are separate, and, as in hedgehogs, spines are mingled with the fur. The true or great tenrec (Centetes ecaudatus), alone repre- senting the typical genus, has the dental formula i. 3 3 2, c. 1, p. I, m. 3 or 4, total 38, 40, 42 or 44. The fourth lower molar, when developed, does not appear till late in life. Of the long and sharp canines, the tips of the lower pair are received into pits in the upper jaw (fig. 9). The creature grows to a length of about a foot. The young have strong white spines arranged in See also:longitudinal lines along the back, but these are lost in the adult which has only a See also:crest of long rigid hairs on the nape of the neck. The lesser tenrecs, Hemicentetes semis pinosus and H. nigriceps, are distinguished by the persistence of the third upper incisor and the form of the skull. The two species are much smaller than the great tenrec, and spines are retained in the adult on the body. The hedgehog-tenrec, Ericulus setosus, has the whole upper surface, and even the short tail, densely covered with close-set spines. The facial bones are much shorter than in the preceding genera, and the first upper incisors are elongated; while there are only two pairs of incisors in each jaw. Judging from the slight development of the cutanecus muscles compared with those of the hedgehog, it would seem that these creatures cannot See also:roll themselves completely into balls in hedgehog-fashion. A second species of this genus, Ericulus (Echinops) telfairi, has two, in place of three, pairs of molars, thus reducing the total number of teeth to 32. Moreover, the zygomatic arches of the skull are reduced to See also:mere threads. Here should perhaps be placed Geogale aurita, a small long-tailed Malagasy insectivore, with 34 teeth, and no spines; the tibia and fibula being separate. It has been classed in the Potamogalidae, but from its See also:habitat such a reference is improbable. The absence of spines may entitle it to separation from the Centetinae, so that it should perhaps be regarded as representing a See also:stile, family, Geogalinae, by itself. The absence of spines coupled with the union of the tibia and fibula form the leading characteristics of the subfamily Oryzorictinae, typified by the See also:rice-tenrecs Oryzorictes, of which there are several species. These creatures, which excavate burrows in the rice-See also:fields of Madagascar, are somewhat mole-like in appearance, but have tails of considerable length. In the typical 0. See also:hove the fore-feet are five-toed, but in 0. tetradactylus the number of front digits is reduced to four. The long-tailed tenrecs (Microgale) are represented by fully half-a-dozen species with tails of great length; that appendage in the typical M. longicaudata being more than double the length of the head and body, and containing no fewer than forty-seven vertebrae. The teeth are generally similar to those of Centetes, but are not spaced in front; their number being i. ;, p. in. Pr, total 4o, ororbits, the descent of the testes into the perineum, and the postinguinal position of the teats, and that none of these are of very great importance. But the See also:geographical positions of the two groups are so widely sundered that it seems preferable to await further See also:evidence before definitely assigning the two to a single family; and the family Solenodontidae may accordingly be retained for the West Indian animals. Solenodons, which look like huge long-nosed, parti-coloured rats, have the tibia and fibula separate, and the same dental formula as Microgale. Each of the two species (which differ in colour and the quality of the fur) has a long cylindrical snout, an elongated naked tail, feet formed for See also:running, and the body clothed with long, coarse fur. The position of the teats on the buttocks is unique among Insectivora. The first upper incisors are much enlarged, and like the other incisors, canines and premolars, closely resemble the corresponding teeth of Myogale; the second lower incisors are much larger than the upper ones, and hollowed out on the inner side. The last family, Chrysochloridae, is represented by the golden moles of South and East Africa, which differ from the Centetidae and Solenodontidae by the development of a bulla to the ttoMea tympanic, and the presence of a zygomatic arch to the See also:Gold skull; the tibia and fibula being separate, and the sym- physis of the pelvis formed merely by ligament. The skull is not constricted across the orbits. The teats, which are placed both on the Fla. 12.—A Golden Mole (Chrysochloris obtusirostris) reduced. breast and in the See also:groin, are situated in shallow depressions. The ears are buried in the fur, and the eyes concealed beneath the skin; the feet are four-toed and provided with powerful claws for burrowing in the fashion of the mole, but it is interesting to See also:note that the skeleton is modified for the same purpose in a manner quite different from that obtaining in the latter animal. These animals derive their name from the metallic iridescence of the fur of most of the species. In the more typical species the dental formula is the same as in Micrcgale, that is to say, there are 40 teeth. In other species, which it has been proposed to separate as Amblysomus, there are, however, only 36 teeth, owing to the absence of the last pair of molars. The .group is evidently nearly related to the Centetidae—most nearly perhaps to the Oryzorictinae. Fossil Insectivora. Some years ago Dr F. Ameghino, of Buenos Aires, described from the See also:Tertiary formation of See also:Santa Cruz, in See also:Patagonia, the remains of an insectivore under the name of Necrolestes. The occurrence of a member of the Insectivora in these beds is remarkable, since this group is represented at the present day in South America only by a shrew or two which have wandered from the north. Dr Ameghino expressed his belief that the extinct Patagonian insectivore was nearly related to the golden moles, and although this See also:opinion appears to have been withdrawn, See also:Professor W. B. See also:Scott states that he is convinced of the close See also:affinity existing between Necrolestes and Chrysochloris. Although this view may not be accepted, it must be re-membered that it represents the opinion of a palaeontologist who has had better opportunities than most of his See also:fellow-workers of forming a trustworthy See also:judgment. So convinced is Dr Scott of the closeness of the relationship between Necrolestes and the golden moles that he regards it as rendering probable the former existence of a See also:direct land-connexion between Africa and South America. There is no See also:reason, he says, to suppose that the track of See also:migration could have been by way of Europe and North America, for no trace of the group has been found anywhere north of the See also:equator. This supposed connexion between Africa and South America in Tertiary times has often been suggested, and is supported by many See also:independent lines of evidence; and the presumed affinity between the two mammals here referred to adds to the See also:weight of such evidence. The See also:discovery in the Oligocene Tertiary deposits of Dakota of the remains of a species of hedgehog is a fact of great See also:interest, for the hedgehog-tribe (Erinaceidae) is at the present day an exclusively Old World group. The discovery of the fossil American species, which has been made the type of a new genus under the name of Protherix, serves to strengthen the view that the northern countries of the Western and Eastern hemispheres form a single zoological region; and that formerly there was comparatively See also:free communication between them in the neighbourhood of See also:Bering See also:Sea, under See also:climatic conditions which permitted of temperate forms passing from one See also:continent to the other. As might have been expected, remains of hedgehog like mammals have been obtained in the Tertiary deposits of Europe. Among these, Palaeoerinaceus, from the Upper Oligocene of See also:France, seems scarcely separable from the existing genus. Necrogymnurus (Neurogymnurus) from the Lower Oligocene, of the same See also:country, appears to be allied to Hylomys, which Is itself the most generalised of the family, so that the extinct genus, of which Caluxolherium is a synonym, may represent the ancestral type of the Erinaceidae. The genus Galerix, or Lanthanoiherium, of the Oligocene, which has the typical series of 44 teeth, a bony ring round the orbit, and conjoint tibia and fibula, has been regarded as representing the Tupaiidae and Macroscelididae, but is more probably, referable to the Erinaceidae, being apparently akin to Gymnura. The moles are represented in the See also:French Oligocene by Amphidozolherium and in the See also:Miocene by Talpa, while in the North American early Tertiary we have the primitive Telpavus. Shrews are also known from the Lower Oligocene upwards both in the eastern and western hemispheres. Of the Lower See also:Eocene Adapisorex, with the typical 22 lower teeth, Adapisoriculus and Orthaspidotherium, all from France, the See also:affinities are quite uncertain. The American Oligocene Leptictis, with i. 2, c. I, p. 4, m. 3 in the upper jaw, and Ictops, with i. , c. }. p. 1, m. may be insectivorous mammals, with affinities to the creodont See also:Carnivora. It is, indeed, probable that not only is there a relationship between the Creodonta and the Insectivora, but also one between the latter and the Marsupialia, so that the marked similarity between the cheek-teeth of the insectivorous Chrysochloris and the Marsupial Notoryctes may be due to genetic relationship. That the bats and the flying-See also:lemur are descendants of the Insectivora cannot be doubted. The best known and most important order of insectivorous See also:plants—Droseraceae—includes six genera: Byblis, Roridula, Drosera, Drosophyllum, Aldrovanda and Dionaea, of which the last three are See also:monotypic, i.e. include only one species. The Sarraceniaceae contain the genera See also:Sarracenia, See also:Darlingtonia, Heliamphora, while the true See also:pitcher plants or Ncpenthaceae consist of the single large genus See also:Nepenthes. These three orders are closely allied and form the series Sarraceniales of the free-petalled See also:section (Choripetalae) of See also:Dicotyledons. The curious pitcher-plant, Cephalotus follicularis, comprises a separate natural order Cephalotaceae, closely allied to the See also:Saxifragaceae. Finally the genera Pinguicula, Utricularia, Genlisea and Polypompholix belong to the gamopetalous order Lentibulariaceae. While the large genus Drosera has an all but world-wide distribution, its congeners are restricted to well-defined and usually comparatively small areas. Thus Drosophyllum occurs only in See also:Portugal and See also:Morocco, Byblis in tropical Australia, and, although Aldrovanda is found in See also:Queensland, in See also:Bengal and in Europe, a wide distribution explained by its aquatic habit, Dionaea is restricted to a few localities in North and South Carolina. Cephalotus occurs only near See also:Albany in Western Australia, Heliamphora on the Roraima Mountains in See also:Venezuela, Darlingtonia on the Sierra See also:Nevada of See also:California, and these three genera too are as yet monotypic; of Sarracenia, however, there are seven known species scattered over the eastern states of North America. The forty species of Nepenthes are mostly natives of the hotter parts of the Indian See also:Archipelago, but a few range into Ceylon, Bengal, See also:Cochin See also:China, and some even occur in tropical Australia on the one hand, and in the See also:Seychelles and Madagascar on the other. Pinguicula is abundant in the north temperate See also:zone, and ranges down the See also:Andes as far as Patagonia; the 250 species of Utricularia are mostly aquatic, and some are found in all See also:save polar regions; their unimportant congeners, Genlisea and Polypompholix, occur in tropical America and south-western Australia respectively. It is remarkable that all the insectivorous plants agree in inhabiting See also:damp heaths, bogs, marshes and similar situations where water is abundant, but where they are not brought into contact with the plenteous See also:supply of inorganic nitrogenous food as are the roots of terrestrial plants. 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