18G(i.] ON THE ANATOMY OF THE CRESTED AGOUTI. 403 



Guinea-pig dissected, an old fleshy male, there was a good-sized 

 fleshy belly to the muscle above the tendon, which latter ended in the 

 thick palmar fascia. 



The flexor sublimis digitorum is quite a small muscle ; it arises 

 fleshy from the internal condyle along with the flexor profundus 

 digitorum, lying rather to the ulnar side of this last. At the wrist 

 it divides on the right limb into three rather delicate tendons, which 

 form the perforated tendons of the second, third, and fourth digits ; 

 on the left limb it sends a division to the fifth digit (fig. 2, F. s. d.). 



In the Hare we find it to have three tendons, going to the same 

 digits as in the right limb of Dasyprocta ; while in the Guinea-pig 

 there are four, as in the left limb of D. cristata. The Rabbit, as 

 Prof. Huxley has observed, is peculiar in having the flexor sublimis 

 dividing into three tendons, with an extra muscle and fleshy belly to 

 the ulnar side of these tendons, which itself sends a tendon to supply 

 the fifth digit. 



Flexor profundus digitorum and flexor h)igus pollicis (fig. 2, 

 F.p. d. and F. I. p. 1, 2, 3, 4). These are represented by a complex 

 muscle consisting of four parts : the first, and much the larger part, 

 arises from the internal condyle ; the second, outer part arises from 

 the shaft of the ulna, its middle three-fourths ; the third part, the 

 smallest, arises in common with the first head, hut rather deeper ; 

 the fourth part (which we take to represent the flexor longus polli- 

 cis 1) arises from the middle three-fourths of the shaft of the radius. 



The first, large portion is fleshy down close to the wrist, and so 

 are the second and fourth portions ; but the smallest portion hecomes 

 tendinous as far up as the middle of the forearm. 



The whole of these tendons form an extraordinarily strong, hard, 

 flat, single tendon, filling the entire interspace between the pisiform 

 and scaphoid bones. In the palm of the hand this mass divides 

 into four very bioad tendons, inserted respectively into the second, 

 third, fourth, and fifth digits ; but no tendon goes to the pollex. 



The component parts and distribution of the tendons of this muscle 

 are the same in the Guinea-pig ; but in the Hare and Rabbit there 

 is an additional tendon to the thumb ; in them also the fourth divi- 

 sion, and not the third, is the smallest one. 



Lumbricales (fig. 2, L.). These seem to be three in number. 

 The first (radial) one arises from the radial side of the conjoined 

 mass of tendon of the flexor profundus and longus pollicis, aud also 

 in part from the index tendon ; it is inserted into the proximal end 

 of the first phalanx of the second digit. The second (middle) one 

 comes from the superficies of the same large conjoined tendon, and 

 partly from the tendons of the index and third digits ; it goes to the 

 radial side of the third digit. The third (ulnar) one has a similar 

 superficial origin from the conjoined tendon and those of the third 

 aud fourth digits ; it is inserted into the ulnar side of the proximal 

 phalanx of the third digit. 



In the Rabbit, Hare, and Guinea-pig there are likewise three 

 lumbrical muscles. Each of these is given off from, and attached to, 

 the radial sides of the third, fourth, and fifth digits. 



