RHYTINIDjE 221 



The Dugongs are more distinctly marine in their habits than the 

 Manatees, feeding chiefly on sea-water algtc. They inhabit the 

 shallow bays and creeks of the Red Sea, east coast of Africa, 

 Ceylon, islands of the Bay of Bengal and the Indo- Malayan 

 Archipelago (including the Philippines), and the north coast of 

 Australia, ranging from Barrow Reefs on the west to Moreton Bay 

 on the east. Although the distinctive characters are not very 

 obvious, they have been divided into three species, according 

 to the localities which they respectively inhabit : — H. tabevnacnli 

 from the Red Sea, H. dugong from the Indian seas, and H. australis 

 from Australia. The last-named has lately been the object of a 

 regular "fishery," chiefly on account of its oil, Avhich is peculiarly 

 clear, limpid, and free from disagreeable smell, and is said to have 

 the same medicinal properties as cod-liver oil. Although often stated 

 in books to attain the length of 20 feet when adult, there does 

 not appear to be any evidence from actual specimens in museums 

 that Dugongs ever reach half that size, 8 feet being the common 

 length of adult animals. 



The placentation of this genus has been recently described by 

 Sir W. Turner, who first indicated its zonary form. 



Family Rhytinid.e. 



Pihjitma} — No teeth, their place being supplied functionally by 

 the dense, strongly-ridged, horny oral plates. Premaxillary rostrum 

 about as long as the anterior narial aperture, and moderately 

 deflected. Vertebras : C 7, D 19, L and C 34-37. Head very small 

 in proportion to the body. Tail with two lateral pointed lobes. 

 Pectoral limbs small and truncated. Skin naked and covered with 

 a very thick, hard, rugged, bark-like epidermis. Stomach without 

 csecal appendages to the pyloric cavity. Cascum simple. 



Only one species of this genus is known, R. stelleri, the Northern 

 Sea-cow, by far the largest animal of the order, attaining the length 

 of 20 to 25 feet. It was formerly an inhabitant of the shores of 

 two small islands in the North Pacific, Behring and the adjacent 

 Copper Island, on the former of which it was discovered by the 

 ill-fated navigator whose name the island bears, when, with his 

 accomplished companion, the German naturalist Steller, he was 

 wrecked upon it in 1741. Twenty-seven years afterwards (1768), 

 as is commonly supposed, the last of the race was killed, 2 and its 



1 Illiger. Prodromus Syst. Me mm. et Avium, p. 141 (1811).— Amended from 

 Bytina. 



2 Nordenskibld, during his voyage in the Vega, obtained some information 

 from the natives of Behring Island which led him to believe that a few individ- 

 uals may have survived to a much later date, even to 1854 ; but this conclusion 

 is disputed by later vmters. 



