THE DUGONG. 379 



The Sireuia are allied to various orders of Mammalia, viz., to 

 the Cetacea or whales, to the pachyderms, according to de Blaiu- 

 ville and others, and possibly to the Ungulates ; but they have 

 peculiarities which distinguish them from all these orders. Their 

 external appearance naturally suggested au affinity with the 

 whales, but a closer examination showed striking points (jf con- 

 trast. The whale, with his huge jaws and enormous head, 

 is carnivorous in its diet, while the Sirenia are herbivorous, their 

 food consisting of aquatic plants, or of marine algte growing in 

 shallow waters. Unlike the whales, their heads are small in 

 proportion to their bodies, and rounded rather than elon- 

 gated. They have, too, this distinguishing peculiarity, that 

 the cervical vertebrte (only six in number in the American 

 species) are free and movable and form a neck enabling 

 the animal to turn its head about, while in the case of the 

 whale, the head and body are united together in one compact 

 masSj the neck being almost immovable. Another pecu- 

 liarity is the formation of the fore-limbs. These, instead of 

 being pectoral fins, as in the whale tribe generally, have the 

 character of the arm and hand of the higher mammalia, whence 

 the name " Manatee", from JIaiius, given to the best known of 

 the living species. The digits of the Manus are not, however, 

 separate, but there is evidence of nails on the end of the fingers, 

 which are united to form a flipper or paddle-like organ. This 

 fore limb, capable of being moved at the elbow joint, is used by 

 the animal to assist in bringing food to its mouth, and in the 

 case of the females, to hold their j'oung to the breast. Their fish- 

 like form and peculiarly human way of suckling their young, 

 suggested to the early navigators the idea of Sirens or mermaids, 

 whence the name given to the order. They have also a few hairs 

 on their thick, wrinkled skins, as Leguat correctly observes, while 

 the whale has a perfectly smooth, glistening, hairless skin. 



It is, however, in their dentition that the Sirenia differ in the 

 most marked way from the whales, and approach the elephant 

 and hippopotamus. The adult Dugong has a pair of tusk-like in- 

 cisors in the upper jaw, and two (rarely three) molars, separated by 

 a wide interval, on each side, above and li»lnw. making fourteen 



