THE SKULLS OF MAMMALIA. 



275 



Eschricht has described, with much care, the changes which 

 the skulls of the BalsenMea undergo in passing from the foetal 

 to the adult condition, justly remarking that the skull of even 

 a large fcetus is more different from that of the adult, than the 

 skulls of distinct species of the same genus of Whales are from 

 one another. 



The growth of the walls of the cranial cavity relatively to 

 that of the external prolongations of the cranial bones and to 



Fig. 110. 



B 



Pin x 



Fjg # no. — A, upper, B, under, and C, side views of the skull ct* a foetal Cachalot in the 

 Museum of the Royal College of Surgeons. The nasal bones are not represented in 

 Fig. a. — N' left, N" right, nostril. The hinder extremity of the jugal, Ju, has fallen 

 down from its natural connection with the zygomatic process of the squamosal. 



T 2 



