184 MR. F. J. BELL ON MOSCHUS MOSCHIFERUS. [Feb. 1, 



In the Pig the digits are all supplied from the common extensor, 

 by its division into four branches ; while the extensor dig. interni, 

 further, is inserted into both the internal digits, and the fifth possesses 

 a proper extensor dig. minimi. 



Now in Moschus each digit is provided with an extensor ; but the 

 so-called common extensor, as in Cervus, sends out only two branches, 

 and these for the median digits, into whose third phalanges they are 

 inserted. The internal extensor is inserted into the first phalanx of 

 the third digit, on its anterior face, and the third phalanx of the 

 second, on its inner face. The external extensor is inserted into the 

 outer sides of the second phalanx of the fourth, and of the third pha- 

 lanx of the fifth digit. A small extensor dig. minimi is also present, 

 and is inserted into its second phalanx, after crossing the extensor of 

 the fourth digit, in the last or distal third of the metacarpus, as in C. 

 virginiamis, as already described, though not as in the Sheep, where 

 this muscle is absent. 



In Tragulus the common extensor is inserted only into the median 

 digits ; but in Hyomoschus, as Chatin says, the arrangement is Por- 

 cine ; that is, the common extensor is inserted into all four digits. 



As in the Sheep and Pig, the extensors of the phalanges arise on 

 the outer side of the radius, and from the external tuberosity of the 

 humerus ; their tendons passing together along a deep groove on the 

 outer face of the distal end of the radius, in a strong fibrous sheath, 

 are directed, according to their destination, more or less inwardly 

 along the anterior face of the metacarpus. Separated from these, 

 however, is the tendon of the internal extensor, the fleshy body of 

 which lies on the flattened outer face of the ulna, while the tendon 

 itself, more deep, has a separate carpal sheath ; when it has passed 

 through this, it widens, but does not bifurcate till it approaches the 

 distal end of the metacarpus. 



/3. Posterior face. 



\A p .f . f flexors of the digits. 



The short flexor of the fifth digit, which is found in the Pig and 

 HyomoscJnis, is absent. 



In no known Ungulate does the pcrforafus send tendons to the 

 lateral digits, but only to the second phalanx of each median digit. 

 In all members of the group its fleshy portion consists of two masses 

 of muscle, arising beneath the fiexor metacarpi obliquus, from the 

 internal condyle of the humerus ; in the Sheep these two tendons, 

 arising from the two muscular masses, one from each, unite in the 

 metacarpal region, and, more distally, bifurcation occurs ; in Cervus 

 virginianus, the two tendons remain separate, as also in the Pig and 

 Hyomoschus. In Moschus, however, there is a certain union of the 

 tendons, by means of a fine slip of tendon running from the inner to 

 the outer branch, in the metacarpal region. 



The perforans, as in the Horse, Sheep, and Pig, consists of three 

 muscular portions, called by Chauvcau e])itrochlcan, ulnar, and radial, 



