100 



TEE BONKS. 



triangle than in the Horse, and the spine gradually decreases from the tuberosity 

 until it is nearly lost on the surface of the bone, towards the nutrient foramen. 

 In the Horse, this subsidence of the spine occurs at the neck, where it takes 

 place quite suddenly ; so that it forms a more or less marked prominence. 



The scapula of the Hinny has the general form of that of the Ass ; in the 

 Mule, on the contrary, it is elongated hke that of the Horse. 



Differential Characters in the Scapula of other Animals, 



The shoulder is composed of one or two bones, according as the limb is intended exclu- 

 sively to support the body, or is required for otiier purposes. 



A. Ox, Sheep, Goat. — In these animals the shoulder comprises only one bone — the 

 scapula — whidi is more regularly triangular tiian in the Horse. The spine does not diminish 

 in passing to the neck, but, on the contrary, terminates at a certain distance above the glenoid 



Fig. 61. 



R A 



SCAPULA OF THE CAT AND RABBIT. 



A, Scapula of the Cat. B, Scapula of the Rabbit. 1, Inferior extremity of the acromian spine j 

 2, supra-spinous fossa ; 3, infra-spinous process ; 4, superior burder. 



cavity by an abrupt ridge prolonged to a point, which represents a rudimentary acromion pro- 

 cess. It divides the external surface of the bone into two fossae, which in extent ure as 1:3. 

 The neck is more constricted, and the humeral angle better detached, than in Solipeds. 



B. Camel. — The scapula of this animal resembles that of the Ox in its general form, but 

 the spine divides the face into two equal fossae. Tiie acromion process descends to the glenoid 

 cavity. 



C. Pig. — The .spine, depressed at its two extremities, ri»es considerably at its middle por- 

 tion, and bends over towards the infra-spinnua process. 



D. Carnivora. — Their shoulder has twobuues— the scapula and clavicle. In the Dog, 

 the latter is little more than a shell embedded in the muscles in front of the scapulo-hunieral 

 angle ; in the Cat, it constitutes a small styloid bone which is united to the acromion proctss 

 and the sternum through the medium of two ligaments. The scapula has no cartilage of pro- 

 longation ; its anterior border is very convex, as if it had been curved over on itself The fossae 

 of the external face are equal, and tlie spine terminates in an acromion process that reaches the 

 glenoid cavity. 



E Rabbit.— Two bones form tlie shoulder of this animal. The clavicle, although longer 

 than that of the Cat. nevertheless does not rest directly on the sternum and scapula. The 

 latter is in shape regularly triangular; the neck is slender; the fossae on the external face 

 are very unequal ; the spine is prolonged by a thin acromion p dicle to the vicinity of the 

 glenoid cavity ; and the superior border of the bone is provided with a cartilage of prolongation. 



