HALICORE. MAMMALIA 161 



on the margin of the pectoral fins ; six cervical vertebrae ; 

 sixteen pairs of thick ribs ; mustaches composed of a bundle 

 of very strong hairs directed downwards, and forming on each 

 side a kind of corn eous tusk. 



The animals of this genus are gregarious, and feed on marine vegetables. The 

 male and female demonstrate much attachment to one another, and tenderness for 

 their young. The female, from the position of the breasts, may have given rise 

 among mariners to the fable of the mermaid. 



M. Americanus, Desm. Head bony, rather elongated ; nasal fora- 

 mina thrice as long as broad ; inferior margin of the lower jaw 

 straight ; skin grayish, slightly shagreened, with isolated hairs. 

 Body sometimes 20 feet long. Inhabits Rivers of S. America. 

 Desm. Nouv. Diet. d'Hist. Nat. xviii. pi. G. 9. 



M. Senegalensis, Desm. (Trichecus Australis, Shaw.) Head bony, 

 short in proportion to its breadth ; breadth of nasal foramina 

 three-fourths of their length ; inferior margin of lower jaw curved; 

 smaller than the preceding. About eight feet long. Inhabits 

 the mouth of the Senegal Shan, i. pi. 69. 



Gen. 147. HALICORE, Cuv. Trichecus, Gmel. Dugun- 

 gus, Lacep. 



Incisors , canines g-, molars f-f, = 14. In early age, in- 

 cisors |, canines g-, molars -f = 32. Two of the upper 

 incisors cylindrical and straight, forming tusks ; molars cylin- 

 drical, and only three on each side in the adults ; body pis- 

 ciform, terminated by a horizontal fin with two lobes ; head 

 not distinct from the body ; muzzle truncated and moveable, 

 with thick spiny hairs on the edges of the lips ; tongue soft ; 

 fins short, without distinct fingers or nails ; seven cervical 

 vertebrae ; eighteen pairs of ribs. 



H. Indicus, Desm. The Dugong. Body pisciform ; two short tusks 

 in the upper jaw, straight and directed obliquely downwards ; 

 lips very thick, spinous ; tail divided into two lobes ; general co- 

 lour bluish gray. 7 or 8 feet long. Inhabits the Indian Seas. 



Gen. 148. STELLERUS, Cuv. Trickecus, Gmel. 



Incisors g, canines g-g, molars f-^ = 4. Teeth not implanted 

 in the jaws, but attached to a molar plate by vessels and nerves ; 

 triturating surface hollowed into tortuous canals ; body en- 

 larged in the centre, diminishing insensibly to the caudal 

 fin ; head obtuse, without distinct neck ; no external ears ; lips 

 double ; a cartilaginous crest to cover the eyes ; anterior ex- 

 tremities in the form of palmated fins ; caudal fin very broad, 

 crescent-shaped, with two points. 



S. Borealis, Desm. (Trick. Borealis, Shaw.) Head round; no 

 tusks ; tail crescent-shaped ; skin naked, excessively thick, and of 

 a fibrous nature, like horn. South Seas. Twenty-three feet long. 



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