104 



THE CAT. 



[chap. IV. 



sub-divisible into three parts : (a) that of the ankle, the tarsus ; 

 (b) that of the middle part of the foot, the metatarsus ; and {c) that 

 of the toes, or digits, composed of phalanges, like those of the 

 digits of the fore-paw. 



§ IS. The OS INNOMINATUM is a large bone, which meets its fellow 



a. Acetabulum. 



Crest of ilium. 

 i7. Ilium. 



ip. nio-pectineal eminence 

 0. Obturator foramen. 



Fig. C4.— The Pelvis, seen in front. 



p. Pul)is. 



s. Sacrum. 



sp. Symphysis pubis. 



1. Tuberosity of ischium. 



of the other side in the mid- ventral line of the body, and is strongly 

 attached to the sacrum {s) above. It thus forms, with the inter- 

 vention of the last-named bone, a solid bony girdle, called the 

 PELVIS, supporting the trunk above, and being itself imposed on 

 the hind-limbs below. The head of the thigh-bone fits into a socket 

 —the acetahulum (a) — on the outer side of the os innominatum. 



This bone consists of two main parts, one above and in front of, 

 and the other below and behind the acetabulum. The upper portion 

 forms one continuous piece of bone, but the lower part is perforated 

 by a largo aperture, termed the obturator foramen (o). Each os 

 innominatum is made up originally of three distinct bones, which 

 become united when the cat is full-grown. These three bones are 

 the ilium, the ischium, and the j;»J/.s. 



