THE ANTERIOR LIMBS. 107 



B. Camel. — The radius of this animal lias a narrow, superior, articulating surface of two 

 glenoid cavities, separated by a median salient crest terminating in front by a very marked 

 corouoid process; the bicipital tul)orosity is large, and on the anterior face. The ulna is very 

 concave in its middle part, and tiie olecrauou is broad and low. 



C. Pig. — Tlie radius is short, its inferior surfait- cut rather obliquely as in Ruminants, and 

 partly formed by the inferior extremity oF tlie ulna, whicii is a volnininous bone provided with 

 a medullary canal, and soii(]ly united to the radius by an interosseous ligament, the complete 

 ossitication of wliich is rare. It is flattened before ami behind, and is spread over the posterior 

 face of the radius, so as nearly to completely cover it. The olecranon is very prominent (Fig. 7t>). 



U. Dog, Cat. — The two bones of tlie forearm are nearly equal in volume, and are in 

 contact only by their extremities, where they show for this purpose : 1. Above, on the ulna, 

 a concave articular surface — the small sigmoid cavity ; and on the radius, a rounded hinge-like 

 facet. 2. Below, two facets analogous to the preceding, but much smaller; that on the radius 

 is concave, and that on the ulna convex. Tliese two bones slightly cross each other, so that the 

 upper end of the ulua touches the radius behind and inwards, while the interior terminates 

 altogether outwards. In the Pig and Ruminants, the lower end is in contact with the upper 

 row of carpal bones (Fig. 77). 



E. Rabbit. — The ulna is still more developed than in the Cat, and more curved length- 

 ways. 



The posterior border of the olecranon ia almost vertical, instead of being oblique from 

 before to behind, and the sigmoid notch is deeper and shorter curved than in the 

 Camivora. 



ANTERIOR (OR FORE) FOOT, OR HAND. 



The anterior foot, or hand, is the region which presents the greatest diffe- 

 rences when it is examined in the various individuals of the animal series. 

 Nevertheless, notwithstanding these varieties, its constitution is fundamentally 

 the same, and may be divided into three sections — the carpus, metacarpus, and 

 phalangeal region. 



In vertebrate animals, the hand is composed of a certain number of parallel 

 or quasi-parallel segments, which constitute the digits. Each complete digit is 

 subdivided into three sections, placed one above the other ; these are, reckoned 

 from above to below — carpus, metacarpus, and phalanges. 



The number of apparent digits varies from one to five ; and, however it may 

 otherwise appear, philosophical anatomy has shown that the hand of all the 

 domesticated animals may be considered as belonging to the pentadactylous 

 type. When it does not appear to be so, this is due to more or less numerous 

 or extensive atrophies or abortions always occurring according to fixed laws. (See 

 remarks hereafter on the Hand in General.) 



1. Carpal Bones (Figs. 67, 68, 69). 



The carpus (or knee) forms the base of the hand. Situated between the 

 inferior extremity of the radius and the superior extremity of the metacarpal bones, 

 it is composed of several small bones joined to each other, in the fresh state, by 

 extremely solid articular bands. Collectively, they form an almost quadrilateral 

 mass, in which may be distinguished two faces and four borders. 



The anterior face is slightly convex from side to side, and irregular ; it is 

 in contact with the tendons of the extensor muscles of the metacarpus and 

 phalanges. 



The posterior face is very unequal, and converted — especially outwardly — into 

 a groove, in which the tendons of the flexor muscles of the phalanges glide. 



