320 VERTEBRATE ANIMALS, 
The only existing Szvenéa are the Manatee (A7anatus) and the 
Dugong (Haiicore), often called “ Sea-cows.” The Manatees 
are found on the east coast of America and on the west coast 
of Africa. They are large awkward animals, attaining a length 
of from eight to ten or fifteen feet, and their flesh is said to be 
very palatable and wholesome. The Dugongs (fig. 173) diffe: 
Fig, 173.—Sirenia. The Dugong (Hadlicore [udicus). 
little in appearance and habits from the Manatees. ‘They are 
found on the coasts of the Indian Ocean and the north coast of 
Australia, and are often killed and eaten. They attain a length 
of from eighteen to twenty feet. The bones of the skeleton are 
remarkable for their extreme hardness and density. 
Besides these living forms, the Szveuza were represented by a 
gigantic species which formerly inhabited Behring Island on 
the coast of Kamtchatka. This animal was described by a M. 
Steller who accompanied Behring on his second expedition, 
and he named it Rkyztina. This enormous animal attained a 
length of twenty-five feet, and a circumference of twenty feet, 
and it appears to have been completely exterminated, no speci- 
men having been seen for two centuries. 
ORDER V. CETACEA.—This order comprises the Whales, 
Dolphins, and Porpoises, and it is characterised by the complete 
adaptation of its members to a watery life. The body is com- 
pletely fish-like in form, the fore-limbs are converted into 
swimming-paddles, and the hind-limbs are completely wanting ; 
whilst the hinder end of the body forms an extremely powerful, 
horizontal caudal fin. Sometimes there is a dorsal fin as well. 
The nostrils may be single or double, but always are placed on 
the top of the head, constituting the “ blow-hole.” The body is 
very sparingly furnished with hairs, or is wholly without them 
in the adult. The head is generally of disproportionately large 
