Online Encyclopedia

tongue is which, instead of being beset with small teeth, are covered by small and fixed in position, with a surface resembling that of the a horny sheath like a See also:

BEAK (early forms beke and becke, from Fr. bec, late Lat. beccus, supposed to be a Gaulish word; the Celtic bec and beq, however, are taken from the English)

beak; there are, however, rasp-like teeth aforesaid plates. The salivary glands are largely developed. The on the See also:

PALATE (Lat. palatum, possibly from the root of pascere, to feed)

palate, and a few on the inner See also:

side of the See also:

LOWER

lower jaw, in- See also:

STOMACH (Gr. vrbsaxos from arbga, a mouth)

stomach is See also:

compound, being divided by a valvular constriction into serted on the s lenial See also:

bone. The See also:

BODY

body is eel-like See also:

black or blackish, See also:

PRINCIPAL

principal cavities, the first of which is provided with a glandular P Y , pouch near the cardiac end, and the second usually with a pair of and only the fore-limbs are present, but are feeble and furnished elongated, conical, caecal sacs or diverticula.

The intestinal See also:

canal is with four fingers. It grows to a length of three feet and inhabits See also:

long, and with very See also:

MUSCULAR

muscular walls. There is a caecum, either marshes in See also:

North and See also:

South Carolina, See also:

FLORIDA

Florida and See also:

TEXAS

Texas. A See also:

SIMPLE

simple, conical, and with extremely thick walls, as in Halicore, or second closely-allied of this family is Pseudobrat2clauscleft, as in Manatus. The See also:

APEX

apex of the See also:

heart is deeply cleft between genus y , the ventricles. The principal See also:

ARTERIES (Gr. ap-rnpia, probably from a"spew, to raise, but popularly connected by the ancients with ai7P, air)

arteries See also:

FORM (Lat. forma)

form extensive and complex differing in having a single branchial See also:

APERTURE (from Lat. aperire, to open)

aperture on each side instead network-like structures, retia mirabilia. The lungs are long and narrow, as, owing to the oblique position of the See also:

DIAPHRAGM (Gr. Scat/pay,aa, a partition)

diaphragm, the thoracic cavity extends far back over the See also:

ABDOMEN (a Latin word, either from abdere, to hide, or from a form adipomen, from adeps, fat)

abdomen. The epiglottis and See also:

ARYTENOID

arytenoid cartilages of the larynx do not form a tubular prolongation. The See also:

BRAIN (A.S. braegen)

brain is comparatively small, with the convolutions on the surface of the cerebrum few and shallow. The kidneys are simple, and the testes abdominal. The uterus is bicornuate. The See also:

PLACENTA (Lat. for a cake)

placenta is non-deciduate and diffuse, the villi being scattered generally over the surface of the chorion except at the poles.

The umbilical vesicle disappears See also:

early. The teats are two, and See also:

PECTORAL

pectoral or rather See also:

POST

post-axillary in position. In vol. lxxvii. of the Zeitschrift See also:

FUR (connected with O. Fr. forre, a sheath or case; so " an outer covering ")

fur wissenschaftliche Zoologie Mr L. See also:

FREUND, WILHELM (1806—1894)

Freund describes in detail the See also:

OSTEOLOGY (Gr. ovTeov, bone)

osteology of the flippers of the See also:

DUGONG

dugong as displayed in " sciograph " pictures. These show that the carpus of the adult consists of three large bones. Of the two in the first See also:

ROW, JOHN (c. 1525—1580)

row, one consists of the fusee: radiate and intermedium, and the other of the ulnare plus the pisiform and the fifth carpale, the lower bone being composed of the four inner carpalia. In the See also:

MANATI (often anglicized as "manatee")

manati the reduction of the carpus has been carried to a less extent, the radiate 'being in some instances distinct from the intermedium, while in other cases in which these two bones are fused the four inner carpalia remain See also:

SEPARATE

separate. Sirenians pass their whole See also:

LIFE

life in See also:

WATER

water, being denizens of shallow bays, estuaries, lagoons and large See also:

rivers, and not met with in the high seas far away from See also:

SHORE

shore. Their See also:

food consists entirely of aquatic See also:

PLANTS

plants, either marine See also:

ALGAE

algae or See also:

FRESHWATER

freshwater See also:

GRASSES

grasses, upon which they browse beneath the surface, as the terrestrial herbivorous mammals do upon the See also:

green pastures on shore. To visit these pastures, they come in with the See also:

flood-See also:

TIDE (O. Eng. lid, cf. Ger. Zeit, time or season, connected with root of Sanskrit a-diti, endless)

tide and return with the ebb. They are generally gregarious, slow and inactive in their movements, mild, inoffensive, and apparently unintelligent in disposition. Though occasionally found stranded by the tide or waves, there is no See also:

EVIDENCE (Lat. evidentia, evideri, to appear clearly)

evidence that they voluntarily leave the water to bask or feed on the shore.

The See also:

HABIT (through the French from Lat. habitus, from habere, to have, hold, or, in a reflective sense, to be in a certain condition; in many of the English senses the French use habitude, not habit)

habit of the dugong of raising its See also:

ROUND (O. Fr. rond, Lat. rotundus, the Fr. is the source also of Du. rond; Ger., Swed., Dan. and Nor. rond)

round See also:

head out of water, and carrying its See also:

young under the fore fin, seems to have given rise, among the early voyagers in the See also:

INDIAN

Indian Ocean, to the legendary beings, See also:

HALF

half human and half See also:

fish, in allusion to which the name Sirenia was bestowed by Illiger. The See also:

SPECIES

species now existing are few. One species, Rhytina gigas of the North Pacific, was exterminated through the agency of See also:

man during the 18th See also:

CENTURY (from Lat. centuria, a division of a hundred men)

century; and the others, being valuable for their flesh as food, for their hides, and especially for the oil obtained from the thick layer of See also:

FAT (O.E. fdett; the word is common to Teutonic languages, cf. Dutch vet, Ger. Fett, &c., and may be ultimately related to Greek Irian, and =apos, and Sanskrit pivan)

fat which lies immediately beneath their skin, diminish in See also:

numbers as civilized populations occupy the regions forming their natural See also:

HABITAT (a French word derived from habiter, Lat. habitare, to dwell)

habitat. The species are confined to the tropical regions of the shores of both sides of the See also:

ATLANTIC

Atlantic and the See also:

GREAT

great rivers which empty themselves into that ocean, and to the coasts of the Indian Ocean from the Red See also:

Sea to North See also:

AUSTRALIA

Australia. As regards dentition (or the want thereof) the three See also:

MODERN

modern genera are remarkably different; and while on this and other grounds some writers refer them to as many separate families, by others they are all included in the Manatidae. In the manatis (Manatus) the incisors, in number, are rudimentary, and concealed beneath the horny mouth, plates, and disappearing before maturity. Molars about fa, but rarely more than present at one See also:

time; the anterior teeth falling before the posterior come into use; similar in characters from beginning to end of the See also:

SERIES (a Latin word from serere, to join)

series; with square, enamelled crowns, the grinding surface raised into tuberculated transverse ridges. The upper teeth with two ridges and three roots, the lower with an additional (posterior) See also:

ridge or See also:

HEEL

heel and two roots. The cervical vertebrae present the See also:

ANOMALY (from Gr. lwvw)

anomaly of being reduced to six in number, the usual vertebral See also:

formula being C 6, D 15-18, L and C, a 25-29. Rostrum of the See also:

SKULL

skull, formed by the See also:

union of the premaxillae in front of the nasal aperture, shorter than the length of the aperture and scarcely deflected from the basi-See also:

CRANIAL

cranial See also:

AXIS (Lat. for " axle ")

axis. Tail entire, rounded or See also:

shovel-shaped. Rudimentary nails on the fore-limbs.

Caecum cleft. Manatis inhabit the shores of, and the great rivers which empty themselves into, the Atlantic within the tropics. The See also:

AMERICAN

American (M. australis) and See also:

AFRICAN

African (M. senegalensis) forms are generally considered distinct species, though they differ but little from each other in anatomical characters and in habits. There is also the small 112. inunguis of the An azon, which has no nails. They are rather fluviatile than marine, ascending large rivers almost to their See also:

SOURCES

sources (see MANATI). In the dugong (Halicore) the upper jaw is furnished with a pair of large, nearly straight, tusk-like incisors, directed downwards and forwards, partially coated with See also:

ENAMEL (formerly " amel," derived through the Fr. amail, emmll, esmail, from a Latin word smaltum, first found in a 9th-century life of Leo IV.)

enamel. In the male they have persistent pulps, and bevelled cutting edges, which project a See also:

SHORT, FRANCIS JOB (1857– )

short distance from the mouth, but in the See also:

FEMALE

female, though they remain through life in the alveolar cavity, they are not exserted, and, the pulp cavity being filled with osteodentine, they soon cease to grow. In the young there is also a second small See also:

DECIDUOUS (from Lat. decidere, to fall down)

deciduous incisor on each side above. At this See also:

AGE (Fr. age, through late Lat. aetaticum, from aetas)

age there are also beneath the horny See also:

PLATE

plate which covers the anterior portion of the mandible four pairs of slender conical teeth lodged in wide socket-like depressions which become absorbed before the See also:

animal reaches maturity. The molars are usually ¢, sometimes s, altogether, but not all in See also:

PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place at once, as the first falls before the last rises above the See also:

GUM (Fr. gomme, Lat. gommi, Gr. Kµµ1, possibly a Coptic word; distinguish " gum," the fleshy covering of the base of a tooth, in O. Eng. gbma, palate, cf. Ger. Gaumen, roof of the mouth; the ultimate origin is probably the root gha, to open wide, seen in

gum; they are more or less cylindrical in See also:

section, except the last, which is compressed and grooved laterally, without distinction into See also:

CROWN

crown and See also:

root, increasing in See also:

SIZE

size from before backwards, with persistent pulps and no enamel. The summits of the crowns are tuberculated before wearing, afterwards flattened or slightly See also:

CONCAVE

concave. Skull with rostrum formed by the union of the premaxillae in front of the nasal aperture, longer than the aperture itself, bending downwards at a right See also:

ANGLE (from the Lat. angulus, a corner, a diminutive, of which the primitive form, angus, does not occur in Latin; cognate are the Lat. angere, to compress into a bend or to strangle, and the Gr. ayKOS, a bend; both connected with the Aryan root ank-, to

angle with the basi-cranial axis, and enclosing the sockets of the large tusks.

Anterior part of the lower jaw See also:

bent down in a corresponding manner. Vertebrae: C 7, D 18-19, L and C 3o. Tail broadly notched in the See also:

MIDDLE

middle See also:

LINE

line, with two pointed lateral lobes. No nails on the fore-limbs. Caecum single. The genus is represented by H. tabernaculi from the Red Sea, H. dugong from the Indian seas and H. australis from Australia. (See DUGONG.) The last genus is represented only by the See also:

EXTINCT

extinct Rhytina gigas, of See also:

BERING (BEHRING), VITUS (1680-1741)

Bering Sea, in which there were no teeth, their place being supplied functionally by the dense, strongly-ridged, horny mouth-plates. Premaxillary rostrum about as long as the anterior narial aperture, and moderately deflected. Vertebrae: C 7, D 19, L and C 34-37. Head very small in proportion to the body. Tail with two lateral pointed lobes. Front limbs small and truncated.

Skin naked and covered with a thick, hard, rugged, bark-like epidermis. Stomach without caecal appendages to the pyloric cavity. Caecum simple. See RHYTINA. Extinct Sirenia.—In past times the Sirenia were represented by a number of extinct generic types ranging over all the temperate and probably tropical regions, and extending from the See also:

PLIOCENE (from the Gr. sr?eiov, mere, and xatvbs, recent)

Pliocene to the See also:

EOCENE (Gr. *In, dawn, icauvos, recent)

Eocene See also:

EPOCH (Gr. E7roxij, holding in suspense, a pause, from E1rxav, to hold up, to stop)

epoch. In the Pliocene of See also:

EUROPE

Europe the See also:

GROUP

group is represented by Felsinotherium, in the See also:

MIOCENE

Miocene by Metaxytherium, and in the Oligocene by Halitherium; the latter having an acetabular cavity to the See also:

PELVIS (Lat. for " basin," cf. Gr. 7rEX?a )

pelvis and a rudimentary femur. From Halitherium, which has a somewhat maniti-like dentition, although there are few cheek-teeth, there is a transition through the other two genera to Halicore; Felsinotherium having a large pair of tusk-like upper teeth. In Halitherium See also:

MILK (0. Eng. meoluc; from a common Indo-European root, cf. Lat. mulgere, Gr. ?t dXyetv)

milk-molars were developed. In Msosiren, of the Belgian Miocene, the teeth were differentiated into i. ;, p. $, m. I.

Remains of several early types of sirenians have been obtained from the Eocene deposits of See also:

EGYPT

Egypt. The least generalized of these is Eosiren, an animal differing from the modern forms chiefly by the retention of traces of the second and third pairs of incisors and of the canines, and the somewhat less degree of reduction in the pelvis, which has a See also:

COMPLETE

complete See also:

ACETABULUM

acetabulum for the head of the femur. The front teeth (incisors and canine) have, however, been thrust to the sides of the )aw, possibly to make See also:

ROOM

room for a horny plate on the palate. In the somewhat earlier Eotherium the incisors and canines are larger and occupy the normal position in the front of the jaws; while the pelvis has a closed obturator foramen and a complete acetabulum, suggestive that a functional thigh-bone or femur was still retained. The most See also:

PRIMITIVE

primitive member of the group with which we are yet acquainted is the very imperfectly known Prorastomus, from the Eocene of the See also:

West Indies, in which a complete and fully differentiated dentition is accompanied by the See also:

ABSENCE (Lat. absentia)

absence of that deflection of the front part of the jaws which constitutes one of the most striking features of all the foregoing representatives of the See also:

order;—a feature which Dr C. W. See also:

Andrews has pointed out must be of great value to short-necked, long. bodied creatures feeding on the herbage at the bottom of the water in which they dwell. The foregoing See also:

EGYPTIAN

Egyptian fossil sirenians afford important evidence with regard to the ancestry of the order. Many years ago it was suggested by the See also:

French naturalist de See also:

Blainville that the Sirenia are related to the See also:

PROBOSCIDEA (animals " with a proboscis ")

Proboscidea. This is supported by the occurrence of the remains of some of the most primitive sirenians with those of the most primitive proboscideans in the Eocene formations of Egypt; confirmatory evidence being yielded by the similarity of the brain and to some extent of the pelvis in the ancestral forms of the two See also:

groups. As regards the living members of the two groups, both have pectoral teats, abdominal testes, and a cleft apex to the heart; while the cheek-teeth of the sirenians are essentially of the same type as those of the early proboscideans. There seems also to be a certain similarity in the mode of See also:

SUCCESSION (Lat. successio, from succedere, to follow after)

succession of the teeth in the more specialized members of the two groups, although in the sirenians this specialization has displayed itself in an abnormal See also:

AUGMENTATION

augmentation of the number of the teeth, while in the proboscideans, on the other See also:

hand, it has taken the form of an increase in the complexity of the individual teeth, especially those at the hinder part of the series.

Finally, although the Proboscidea have a deciduate and the Sirenia a zonary nondeciduate placenta, yet there are certain similarities in the structure of this See also:

ORGAN

organ in the two groups which may indicate genetic See also:

affinity.

End of Article: SIREN

Additional information and Comments

There are no comments yet for this article.

» Add information or comments to this article.

Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML.

Site content, images, and layout Copyright © 2006 - Net Industries, worldwide.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.

Links to articles and home page are always encouraged.

[back]
SIRDAR, or SARDAR (Persian sardar, meaning a leader...

[next]
SIRENS (Gr. Metpi7ves)