MAMMALIA 



641 



The cat walks on the digits with the remainder of the hand or foot 

 failing to reach the ground. This is known as the digitigrade gait. 

 Man and bears use the plantigrade or primitive gait in which the 

 entire sole and heel make contact with the ground. 



Skeleton 



Exclusive of the teeth, ear bones, chevron bones, and sesamoid 

 bones a young fully developed cat has 233 bones. In addition to 

 the bones there is some cartilage. This skeleton is made up of 

 cartilage-hones, which are preformed in cartilage and replaced by 

 bone, and memhrane-hones, a bone formation in the dermis of certain 

 portions of the skin. The sesamoid ho7ies are pieces formed in ten- 

 dons. The kneecap is the largest of these. Chevron hones are paired 

 and extend ventrally from the anterior ends of several of the caudal 

 or tail vertehrae. 



NEURAL SPINE 

 POST ZYGAPOPHYSIS 

 ACCESSORY PROCESS 

 ARTICULATING SURFACE 

 OF PRE-ZYGAPOPHYSIS 



NEURAL CANAL 



CENTRUM 



TRANSVERSE PROCESS 



Fig. 347. — Anterodorsal view of lumbar vertebrae of cat. (Drawn by Titus Evans.) 



The axial skeleton, as is usual in vertebrates, is the portion extend- 

 ing in the main axis of the body and is composed of skull, vertebral 

 column, ribs, and sternum. There are twenty-six bones that are 

 usually named and described in the cat's skull. These bones are for 

 the most part immovably fused together at sutures. In the most 

 anterior or frontal segment of the skull proper are the two frontal 

 hones, dorsally, the presphenoid and two orhitosphenoid-s. Behind this 

 is a middle or parietal segment composed of the hasisphenoid, two ali- 

 sphenoids, and the two dorsal parieiaU. The most posterior or 

 occipital segment represents a fusion of four bones. It consists of 

 hasioccipital, two exoccipitals, and the supraoccipital. In addition 

 to these rings or segments there are three sense capsules, the olfactory 



