SKELETON.] 



THE HOESE, AND 



[skeleton. 



altliough a different modification of the entire 

 skeleton may be traced in the animals with 

 toes in even number, as compared with the 

 horse and other odd-toed hoofed quadrupeds. 



HORSE (Eqmcs Cahallus). 

 The vertebral formula of the horse is — 7 

 cervical, C ; 19 dorsal, D ; 5 lumbar, L ; 5 sa- 

 cral, 8; and 17 caudal. Eight pairs of ribs 

 directly join the sternum, 60, which consists 

 of seven bones and an ensiform cartilage. The 

 neural arches of the last five cervical vertebrse 

 expand above into flattened, subquadrate, hori- 

 zontal plates of bone, with a rough tubercle in 

 place of a spine ; the zygapophyses, z, are un- 

 usually large. The perforated transverse pro- 

 cess sends a pleurapophysis, pi, downwards and 

 forwards, and a diapophysis, d, backwards and 

 outwards, in the third to the sixth cervicals 

 inclusive ; in the seventh the diapophysial part 

 alone is developed, and is imperforate. The 

 spinous processes suddenly and considerably 

 increase in length in the first three dorsals, 

 and attain their greatest length in the fifth 

 and sixth, after which they gradually shorten 

 to the thirteenth, and continue of the same 

 length to the last lumbar. The lumbar dia- 

 pophyses are long, broad, and in close juxta- 

 position ; the last presents an articular con- 

 cavity, adapted to a corresponding convexity 

 on the fore part of the diapophysis of the first 

 sacral. The scapula, 51, is long and narrow ; 

 and, according to its length and obliquity of 

 position, the muscles attached to it, which act 

 174 



upon the humerus, operate with more vigour ; 

 and to this bone the attention of the buyer 

 should be directed, as indicative of one of the 

 good points of a horse. The carocoid is 

 reduced to a mere con- 

 fluent knob. The spine 

 of the scapula, 51, has no 

 acromion. The humerus, 

 53, is remarkable for the 

 size and strength of the 

 proximal tuberosities, in 

 which the scapular mus- 

 cles are implanted. The 

 joint between it and the 

 scapula is not fettered by 

 any bony bar connecting 

 the blade- bone with the 

 breast-bone ; in other 

 words, there is no clavicle. 

 The ulna, represented by 

 itsolecranal extremity, 54, 

 is confluent with the radi- 

 us, 55. The OS magnum, in 

 the second series of carpal 

 bones, 5Q, is remarkable for its great breadth, 

 corresponding to the enormous development of 

 the metacarpal bone of the middle toe, which 

 forms the chief part of the foot. Splint-shaped 

 rudiments of the metacarpals, answering to the 

 second, ii, and fourth, iv, of the pentadactyle 

 foot, are articulated respectively to the trape- 

 zoides and the reduced homologue of the unci- 

 forme. The mid- digit, Hi, consists of the me- 

 tacarpal, called "cannon-bone," and of the 

 three phalanges, which have likewise received 

 special names in veterinary anatomy, for the 

 same reason as other bones have received them 

 in human anatomy. " Phalanges" is the gen- 

 eral term of these bones, as being indicative 

 of the class to which they belong; and " hae- 

 mapophyses" is the general term of parts of 

 the inferior arches of the head-segments ; and 

 just as from the modifications of these hsema- 

 pophyses, they have come to be called " max- 

 illa," "mandibula," '• ceratohyal," &c. ; so the 

 phalanges of the horse's foot are called — the 

 first, "great pastern bone;" the second, " small 

 pastern bone;" and the third, which supports 

 the hoof, the " coffin-bone ;" a sesamoid ossicle 

 between this and the second, is called the 

 "caronary." The ilium, 52, is long, oblique, 

 and narrow, like its homotype, the scapula; 



