The appendicular muscles of Necturus uiaculosus. 419 



corresponds closely to its homolog in the arm, except that its area 

 of insertion, in accord with the difference in the general form of 

 the muscle, is somewhat different in shape (cf. Figs. 36 and 37, 

 fr and ftb). 



M. pronator (pr). This musle, in position, direction, and use, 

 corresponds closely to its homolog in the arm, but it is much broader 

 at its origin. This area, in the form of a longitndinal line, includes 

 nearly the entire length of the fibula and crosses almost the whole 

 of the fibulointermedium, while that of its anterior homolog is con- 

 fined to the middle part of the shaft of the ulna. It inserts by 

 two slips, the one into the middle of the dorsal surface of tarsale 2 r 

 the other into the tibial side of the base of metatarsale IL 



Mm. flexores breves superficiales (fbs). Except, per- 

 hapSj in the detail of the bundles, which appear to be somewhat 

 variable individually, I have fonnd a complete correspondence be- 

 tween these small digital muscles and these of the same name in 

 the hancl. There are four slips, one for each digit, and they arise 

 from the dorsal (inner) surface of the plantar fascia, that is, in part 

 from the crescentic ligament that binds the latter to the tarsalia 

 and in part from the fascia distal to this and proximal to the point 

 at which the latter splits into the four slips destined for the four 

 digits. Each of these four muscle masses is in itself Compound, 

 and is divisible into separate bundles, typically five in number, one 

 median and, for each side of the digit, two lateral ones, exactly as 

 in the hand. At the point of origin, in both foot and hand, these 

 divisions are not always distinct, and the ultimate number may be 

 reached, either by a primary division of the bündle into three, one 

 for the middle and one for each side, the lateral ones dividing again, 

 or eise by a primary division into the five typical bundles. The 

 first of these methods is shown in the illustrations of the hand, 

 and the last in digit IV of the foot. Quite often, too, the median 

 bündle seems to be continuous with the lateral one upon one side, 

 making an apparant total of four, as is shown in digits II and III 

 of the foot. These differences seem to be in part individual and 

 in part due to the chance of dissection, as the Separation of the 

 slips at their origin is to some extent an artificial one although 

 the insertions are definite. Attention may here be called to the 

 precise correspondence of digit IV in hand and foot, even to the 

 interpolation of the little interphalangeus in both (Figs. 34 and 35). 

 The little über seen in Fig. 34 connecting the interphalangeus wil h 



27* 



