AND PHYSIOLOGY. 



89 



in two pieces. In nearly all the orders of mammalia this 

 bone (the frontal) is always found in two pieces. In the 

 Elephant the bones of the cranium are all united into one 

 at an early period in life, forming but one piece, in order 

 probably to make it sufficiently strong to support the great 

 weight which i3 brought upon these bones by the tusks 

 and proboscis. The Styloid process of the temporal bone 

 is usually in mammals a separate ossicle. The bone which 

 contains the organ of hearing in all mammals, except 

 man and the Apes, is a separate bone called the Tympanic, 

 and is not simply the petrous portion of the temporal as in 

 man. 



196. Bones of Face, Intermaxillaries, Lower Jaw. — 

 In the Face too the bones correspond very nearly with those 

 in man. The essential difference is found in the upper jaw. 

 Instead of the two superior maxillaries meeting each other on 

 the median line of the body in front, there are two other bones 

 between them called the Intermaxillaries. These are very 

 conspicuous in animals provided with large canine teeth, or 

 tusks, as the Elephant and Squirrel. The Lower Jaw in 



What peculiarity about the bones of the Elephant's skull ? W r hat bone Is wanting in 

 the Whale ? Describe the Tympanic Bone. 196. In what respect do the bones of tho 

 face in Mammals differ from those in man ? Where are the Intermaxillaries ? 



