OF THE CLASS MAMMALIA. 



303 



Manatee of Senegal Unknown. 



Delphinus Delphis 67, Cuvier. 



Delphinis Grisens 61, Cuvier. 



Dolphin in our Museum 81, Knox. 



Dolphin in Dr. Hunter's Museum, Glasgow 90, Knox. 

 Dolphin dissected by Mr. John Hunter, \ 



and considered by him as the D. Delphis, J 60, Hunter. 



but by M. Cuvier as the D. Tursio . 



Phocaena. 



N.B. This discrepancy in the number of 

 Phocaena may be specific ; but this is not likely. 



66, Cuvier. 

 65, Knox. 

 51, Hunter, 

 vertebrae in the 

 E. K.] 



423. The division of the mammalia called didelphian, 

 is characterized by physiological distinctions of great impor- 

 tance. In general the young are born prematurely, as it 

 were, and exceedingly imperfect, and they seem, whilst in the 

 womb, not to be nourished by a placenta, as is the case with 



Fig. 280. Kangaroo. 



all the monodelphs. The brain is comparatively smooth, 

 and without a corpus callosum ; and marsupial bones attached 

 to the pelvis (Fig. 212), give a peculiar character to the 

 skeleton. 



This group is composed of two orders the marsupial and 

 monotremes. 



