154 ANATOMY OF THE WOOD RAT 



Upon digit one are inserted tendons of the extensor indicis 

 and the third head of the flexor digitorum profundus. Upon 

 digit two are a tendon of the extensor digitorum communis, 

 extensor indicis, flexor digitorum sublimis, and tendons from 

 two heads of the flexor digitorum profundus. On digit three 

 are inserted two tendons from the extensor digitorum 

 communis, one from the flexor digitorum sublimis, and two 

 heads of the flexor digitorum profundus. Digit four has 

 tendons from the extensores digiti quinti and digitorum 

 communis, and from the flexores digitorum sublimis and the 

 third head of the digitorum profundus. On digit five are the 

 extensores digiti quinti and digitorum communis, and third 

 head of the flexor profundus. In Teonoma the extensor 

 digitorum communis and flexor digitorum sublimis muscles, 

 with their distal tendons, are appreciably more robust, and in 

 addition, the latter muscle sends a fifth tendon to digit five. 

 The lateral side of the manus in this subgenus is strengthened 

 to just this extent. 



Pelvic girdle 



As with the pectoral girdle, the affinity of the pelvic girdle 

 is supposed to be with the vertebral column rather than with 

 the limbs; but the functions of the muscles attached to it 

 make it far more convenient to discuss this girdle in con- 

 nection with the neighboring appendages. 



The pectoral girdle is formed by the two innominate bones, 

 the greatest length of which varies from about 32 to 35 per 

 cent of the vertebral body length. There is almost no sub- 

 generic variation in this respect. Each innominate consists 

 of four bones, as figured. The ilium is the one most craniad, 

 extending to the acetabulum; the cotyloid bone comprises 

 most of the acetabulum and articulates with the three other 

 bones, but does not extend to the medial surface of the in- 

 nominate; the ischium forms the caudo-dorsal portion of the 

 innominate, articulating at the sjTuphysis with the pubis, 



