CETACEANS. 



591 



The largest bats are the fruit bats or flying foxes (Ptero- 

 pus] of the East Indies; one species of which expands one and 

 a half metres (nearly five feet) from 

 tip to tip of the wings. Our com- | 3 _, 

 -monest species is the little brown f of ' 

 bat, Vespertilio subulatus of Say ; ' 

 nearly as common is the red bat, 

 AtalapJia noveboracensis Coues. 



Order 5. Cete (Cetaced).W& 

 now come to the Educabilia, in 

 which the brain is more highly de- 

 veloped, and begin with two very 

 aberrant orders, the whales and 

 Sirenians, in which the body is 

 fish-like, though the tail is hori- 

 zontal ; the pelvis and hind limbs 

 are wanting, either wholly, or mi- 

 nute rudiments may be present; 

 and they are aquatic, occasionally 

 leaping out of the water, but usu- 

 ally only showing the dorsal fin or 

 nose when at the surface to breathe. 



The whales and porpoises have 

 a large, broad brain, with numer- 

 ous and complicated deep convolu- 

 tions. 



In the skull (Figs. 512, 513) the 

 aperture for the spinal cord (fora- 

 men magnum] is entirely posterior 

 in situation and directed some- 

 what upward. The lower jaw is 

 straight, with no ascending ramus, 

 the narrow condyles being situated 

 at; the end of the jaw, at the point 

 indicated by the angle of the ramus 

 in other mammals. The teeth are 

 conical, with a single root, but are 

 sometimes wanting. There is no neck ; the cervical verte- 

 bra? are sometimes confluent, forming a single mass. The 



