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Show 204 MAMMALIA. wht. ch soon d't sapp eat· · ·Vestiges of nails . are discoverable on. th.e edges o f t h e·t r fi ns, which th. ey empl.o y wtth tolerable dexte. rtty m carry·m g t h e·t r you ng, and m creepmg; hence the comp.a rtson of these organs w1' th hands ' and the name. of Manatus ap. phed to the am· ma1 , of w 1H ·C h Lamantin is a corruptwn. From theH•· manner of I. · they are also called Sea Cows, &c., and from thetr mammce, tvmg, · .tr XIII 1 .. ..utr .1.ermm' ds , &.c.-Trichechus manatus, Lm.; .B un. · h , hv u • They are found near the mouths of rtvers m t e ottest p.arts of the Atlantic Ocean, and it appears that those .of .the Amencan rivers are specifically different from those of Afrtca. ( 1) They grow to the length of fifteen feet. Their flesh is used as food. HALICORE, Il1ig.(2)-DuGONG, Lacep. Grinders composed of two cones laterally united; the teeth implanted m· t h e m· ct· st· ve bone are permanent , and increase to such an ext.e nt as to become true pointed tusks, but covered by thick fleshy hp~, bristled with mustachios. The body is elongated, .and the tali terminated by a crescent-shaped fin. One species only 1s known, the Hal. dugong; Siren; Sea Cow, &c.; Renard, Poiss. des Ind~s, pl. xxxiv, f. 180; Home, Phil. Trans. and F. Cu.v. Mamm1f. (The Dugong.) It inhabits the Indian Ocean, and IS frequently confounded by travellers with the Manatus. STELLERus, Cuv.-RYTINA, Illig.(3) The Stelleri appear to have but a single compound grinder on ea~h side, with a flat crown, and bristled with plates of enamel. Their fins have not even the little nails observed on those of the Manatus. According to Steller, the fi1·st, and hitherto the only one who has de· scribed them, their stomach also is much more simple. One species only is known, which is confined to the north part of the Pacific Ocean. ( 4) FAMILY II. CETACEA ORDINARIA. The Ordinary Cetacea are distinguished from the preceding by the singular apparatus from which they have received the (1} See Oss. Foss. tom. I. (2) Halicore, Maid of the Sea. ( 3) Rytina, wrinkled. (4) Nov. Comm. Petrop. II, 294, et seq. lthas never been figured. CETACEA. 205 name of Blowers. As a large quantity of water passes into their huge mouths along with their prey, some way was necessary by which they could get rid of it; accordingly, it passes through the nostrils by means of a peculiar disposition of the velum palati, and is accumulated in a sac situated at the external orifice of the cavity of the nose, whence, by the compression of powerful muscles, it is violently expelled through a narrow opening on the top of the head. It is in this way they produce those jets d'eau observed by navigators at so great a distance. Their nostrils, continually bathed in salt water, could not be lined with a membrane sufficiently delicate to enable them to detect odours, and accordingly, they have none of those projecting laminre found in the nasal cavities of other animals; the olfactory nerve is deficient in several, and if there be any which enjoy the sense of smell, it must be in a very slight degree. Their larynx, of a pyramidal form, penetrates into the posterior nares to receive air and conduct it to the lungs, without compelling the animal to raise its head and throat above the water for that purpose : there are no salient laminre in the glottis, and the voice is reduced to a simple lowing. They have no vestige of hairs, but their whole body is covered with a smooth skin, under which is that thick layer of blubber abounding in oil, the principal object for which they are pursued. Their mammre are near the anus, and their fins are incapable of grasping. The stomach is divided into five and sometimes into seven distinct sacs; instead of one single spleen, they have several, small and globular ; those which are possessed of teeth, have them all conical and alike ; they do not chew their food, but swallow it rapidly. Two small bones suspended in the flesh, near the anus, are the only vestiges of posterior extremities. . Several have a vertical fin on the back, composed of a tendinous substance, but unsupported by bone. Their eyes, flattened in front, have a thick and solid sclerotica ; the teguments of the tongue are soft and smooth. They may be again divided into two small tribes : those in. |
