1916] Holliger: Anatomical Adaptations in the Pocket Gopher 479 



arm. Here its tendon passes over the tendons of muscles 28 and 29 

 and is inserted on the radial side of the base of metacarpal 1. This 

 muscle is an extensor of the manus and pollex, and possibly also 

 has a supinating action. It doubtless corresponds to the extensor 

 ossi metacarpi pollicis in man. 



31. Extensor digitorum communis {ex. dig. com., fig. Q) arises 

 by the common extensor tendon from the external condyle of the 

 humerus. Near its origin it begins to divide and its parts end in 

 four tendons which pass deeply under the annular ligament of the 

 wrist. The tendons then diverge and are inserted into the bases 

 of the terminal phalanges of digits 2, 3, 4, and 5 (ex. dig. com., 

 pL 38). This muscle extends first the digits and then the entire 

 manus. 



82. Extensor pollicis et indicis {ex. pol. ind., fig. S) arises in 

 common with the extensor group of muscles, on the lateral condyle of 

 the humerus. Its tendon accompanies those of the preceding 

 muscles under the annular ligament. It becomes superficial in the 

 metacarpal region, and divides into two parts, the mesial of which 

 is inserted at the base of the distal phalanx of the pollex, and the 

 lateral on the distal end of the dorsal surface of metacarpal 2. Its 

 action is to extend digits 1 and 2, and by further action, the manus. 



33. Extensor digiti quinti proprius {ex. dig. q. pr., fig. Q) 

 arises by the common extensor tendon, and is inserted by two tendons, 

 one in the distal end of the dorsal surface of metacarpal 5, and 

 the other in -the base of the terminal phalanx of digit 5 {ex. dig. 

 q. pr., pi, 38). This muscle extends the fifth digit and, like the 

 preceding, serves to stiffen the carpal articulation. 



34. Extensor carpi ulnaris {ex. car. id., fig. Q) arises on the 

 lateral surface of the ulna in a curved line just posterior to the 

 origin of the abductor pollicis {ex. car. id., pi. 38), and is inserted 

 on the base of the lateral surface of metacarpal 5. This muscle 

 extends and abducts the wrist. 



35. Palmaris longus {palm,, lo., fig. R) arises on the internal 

 condyle of the humerus in common with the flexor group of muscles. 

 It is superficial for its entire length, and is inserted into the palmar 

 fascia. In the gopher this muscle is relatively large and is a strong 

 flexor of the manus. 



36. Flexor carpi ulnaris {fix. car. ul., fig. R). — This is the 

 largest muscle in the forearm of the gopher; it is superficial on the 

 whole caudal surface of the forearm. This muscle arises on the 



