)0Q 

 J'JO 



ZOOLOGY 



The muscles of the breast and appendages offer special com- 

 phcations. 



The nervous system shows an advance over that of fishes. 

 The brain has two large lobes in front (olfactory lobes, 

 ol.lohe) , but the front part of the brain proper (cerebrum) and 



Fig. 31S. — Mud-puppy (Necturus), photographed while Uving in an aqua- 

 rium. From Report N. Y. Zoological Society. 



the cerebellum are poorlj- developed. The spinal cord is 

 shortened and modified on account of the shortening of the 

 trunk. 



Sense-organs. — The sense of smell is chiefly located in the 

 nasal sacs, which open anteriorly to the exterior and posteriorly 

 into the mouth. The eye is essentially hke that of other verte- 

 brates. The ear also consists of a central chamlicr and three 

 semicircular canals. There is a large external membrane, and 



