SIRENIA. 



269 



diaphragm, is most unusually lengthened backwards. The apex of the heart is cleft, giving the ap- 

 pearance of a double organ, and the blood-vessels almost everywhere in the body and limbs split 

 into rete mirabile. The stomach has two main digestive chambers, and to the first is added a pair of 

 small divergent horn-shaped appendages, besides a remarkable finger-shaped gland. Unlike Whales 

 or Elephants their small brain has few convolutions. All the bones are dense and heavy, and are the 

 most solid among Mammals. Manatus is unique among the living Mammalia in having but six neck 

 vertebrae, and, as in the other Sirenia, they are all separate. The ribs are uncommonly thick. The skull 

 is relatively much smaller than in the Cetacea, is low set, somewhat elongated, and truncated at each 

 extremity. The side bones (parietals) meet above, the occiput is small, the orbits well defined, and 

 the nasal passages are directed forwards ; the lower jaw has a high vertical limb (or ramus) behind, 

 and in the Dugong the upper and lower jaw-bones are strangely bent down. The Sirenia are 

 animals of slow habit, and are most inoffensive. They feed solely on aquatic vegetation. As being 

 the most Whale-like in size and shape of tail, we shall first introduce to notice the Rhytina. 



STELLER'S RHYTINA,* the Morskaia Korava of the Russians, and alone representative of the 

 genus, is a creature now extinct, but which was living and in tolerable abundance a hundred and fifty 

 years ago. When the Russian, Behring after whom the Strait is named first visited that region 

 and the neighbourhood of Kamstchatka, thei'e existed a huge animal, of which, under the name of 

 Manatee, or Northern Sea Cow ( Vacca marina), the naturalist Steller, who accompanied him, gave a 

 classical account. It had a small oblong head, a full bristly snout, a dark-coloured body, protected by 

 a rugged, gnarled, warty, hairless skin. The fore limbs were quite short and stumpy, hairy at their 

 ends, and they had no finger-bones beyond the wrist. The tail was black, ending in a horizontal, 

 stiff, half-moon-shaped, narrow fin-blade, fringed with a fibrous whalebone-like material. It had 

 no teeth, but horny, almost bony plates, corresponding to the horny gum-pads of the Dugong and 

 Manatee, served the purpose of mastication. According to Steller, it attained a length of from twenty 

 to twenty-eight feet. 



Though stupid, voiceless, animals, they were of a very affectionate disposition, and were readily 

 tamed, even allowing themselves to be handled. Their conjugal affection was strikingly developed. 

 A male, who in vain attempted to relieve his partner, stuck by her, in spite of repeated blows, and 

 when she died he returned to the spot for some days, as if he expected to see her again. They were 

 very voracioiis, and fed on seaweeds, with their heads under water ; and every now and then they raised 

 their noses to breathe, and made a snorting noise. They appeared in families, each consisting of a 

 male, female, one half grown, and a cub born in autumn ; and sometimes these families united into 

 great herds. As they were very good eating (far preferable to salt junk), Steller recommended them 

 as articles of diet to the sailors ; and so faithfully was his advice observed by natives and seamen, that 

 within twenty-seven years of his first visit the last "Rhytina was killed, namely, in 1768. They 

 were hunted with a boat-hook attached to a long rope, which, when the animal was struck, was 

 passed to a company of men on shore, who, with considerable difficulty, managed to land the huge Sea 

 Cow. This animal appears to have had an extremely limited range, having never been met with any- 

 where but in the small Behring Island, off the coast of Kamstchatka. Their sudden extinction is a 

 most noteworthy fact, and but for Steller's admirable account nothing whatsoever would have been 

 known of the habits, internal structure, or outward appearance of this singular Sirenian. Though the 

 adults were toothless, yet by some it is supposed from analogy that in early life functionless teeth may 

 have existed, though these never appeared above the gums. The Rhytina, in its forked tail, somewhat 

 down-bent jaws, and other points, resembled the Dugong ; while in skull characters and skin it was 

 like the Manatee ; and though somewhat whale-shaped, it was a true Sirenian. 



THE DUGONG, t typical of the genus Halicore, is a living form, ordinarily from ten to twelve 

 feet long, though very old males are said occasionally to reach as much as eighteen to twenty feet. 

 Its distribution is rather widespread, namely, from the Red Sea and East African coasts to thp- west 

 coast of Australia ; and they are even yet not unfrequently met with within these limits, on the 

 coasts of Mauritius, Ceylon, and the Indian Archipelago, though in numbers fast becoming thinned. 

 Outwardly they differ from the Rhytina in being smoother-skinned, and in having the fore-limbs 

 longer, and the tail semi-lunar, but deeper or less fluked, and not marginally split. Their colour is 

 * Rhytina SleUeri. f Halicore duyong. 



