ANATOMICAL STRUCTURE OF ANTHROPOID APES. 73 



panzee's skull admits of a whole system of cavities 

 communicating with each other, which are of tlie 

 nature of the so-called sinuses 

 present in the frontal, sphenoid, 

 ethmoid, and maxillary bones of 

 the human skull. In the chim- 

 panzee, however, the sinuses are 

 more extensive than in man, or 

 even than in the gorilla. The Pig. 20— skuiiofa very 



, . ^ . n , 1 nil young female chimpanzee. 



large cavities 01 the lorehead 

 communicate with those of the nose and jaws. The 

 sphenoidal sinuses and ethmoidal cells are large 

 and deep. The greater wings of the sphenoid bone 

 and its pterygoid processes are provided with con- 

 siderable cavities. The mastoid cells of the tem- 

 poral bones are in connection with the cells of the 

 greater wings and pterygoid processes of the sphe- 

 noid bone, and also extend through the squamous 

 portions and zygomatic processes of the temporal 

 bones, losing themselves in their upper part in the 

 smaller cells of cancellous bone which are found 

 between the outer and inner walls of the skull. 

 These are of more uniform shape and size. 



The skeleton of the chimpanzee, in accordance 

 with the smaller size of the species, is relatively 

 of a slenderer build than that of the gorilla. 

 The spinous processes of the seven cervical ver- 

 tebrae are more slightly developed, and have 

 undivided extremities. The transverse processes of 

 the fifth and sixth cervical vertebr?e are almost of 

 the same shape as cervical ribs. There are thirteen 

 dorsal vertebrae, somewhat laterally compressed : 



