MAMMALIA — OPOSSUM. 213 



say, that they live on the broad leaves of a certain vegetable which grows 

 in the sea, and that they eat neither flesh nor fish. But I imagine all these 

 opinions have but a weak foundation ; and there is reason to think, that the 

 walrus, like the seal, lives on prey, especially herrings and other fish ; for 

 it does not eat at all when upon land, and it is chiefly hunger which obliges 

 it to return to the sea. 



The fat of the walrus furnishes from one to two barrels of oil ; and the 

 skin is capable of being manufactured into a strong and elastic leather. 



ORDER FIVE — MAR SUPI ALIA. 

 Animals of this order have teeth different in the different genera. The 

 young are brought forth prematurely, often into a pouch formed by a fold of 

 the skin of the abdomen of the females, inclosing the mammse ; marsupial 

 bones in both sexes ; thumb of the hind feet sometimes wanting, sometimes 

 very distinct, without nail, opposable to the other toes. 



THE VIRGINIAN OPOSSUM. i 



The opossum is found in Brazil, Guiana, Mexico, Florida, Virginia, and 

 other temperate regions of this continent. The female has under the belly 

 a large cavity, where she receives and suckles her young ; she produces 

 often, and a great number of young each time, most authors say, four or 

 five, others six or seven. 



' Didelphis Virsrinlana, Penn. The genus Didclphis has ten upper and eii^ht lower inci- 

 sors ; two upper and two lower canines ; twelve orfourleen upper and fourteen lower molars. 

 Two superior intermediate incisors larger than the others ; lower incisors equal; canines 

 strong, compressed molars, the three first in the upper jaw triangular ; the others crown- 

 ed with points ; head long and conical; muzzle pointed, mouth much cleft ; ears large, 

 rounded and almost naked; five toes on all the feet; nail- longandbent; hind feet planti- 

 grade with the thumbs opposable, but destitute of nails ; tail long, scaly, mostly de- 

 prived of hair. ■> 



