J. Playfair McMurrich ATS 
and in Amblystoma is partly directly continuous with the abductor. 
Furthermore, the continuity of the line of origin of the abductor with 
that of the flexor brevis superficialis and its origin in part from the 
ulnar margin of the palmar aponeurosis are facts of no little import- 
ance. The distinctness of the abductor except at its origin from the 
rest of the flexor superficialis need have but little weight, since even 
in the amphibia a distinct separation of the lateral portions of the 
palmaris superficialis as the flexores carpi ulnaris and radialis is already 
in existence, and the continuity of the flexor carpi ulnaris with the 
abductor might well contribute to a separation of the latter. Nor does 
a fusion of a portion of the flexor brevis superficialis with a muscle 
belonging to the flexor profundus seem improbable, since there is 
typically such a fusion in the amphibian hand in the cases of the 
various slips to the digits. 
Accepting then the superficial nature of the abductor we find in 
the reptilia an interesting rearrangement of the muscles which consti- 
tute the flexor brevis profundus as compared with the condition in the 
amphibia. The portion to each digit is practically reduced to two slips 
and, what is more important, one of these slips assumes an oblique 
direction, passing across an intermetacarpal space to be inserted into 
the digit adjacent to that from which it arises. I emphasize this ar- 
rangement of the profundus slips since it has important bearings upon 
the arrangement assumed by the corresponding muscles in the mam- 
maha. 
The Intermetacarpales—These muscles (Figs. 3 and 5, Im) have 
entirely lost their muscular structure and have been converted into 
strong tendinous bands which extend obliquely across the various inter- 
metacarpal spaces. The three radial tendons are directed ulnarly and 
distally, being attached at one extremity tc about the middle of the 
ulnar side of the first, second and third metacarpals and passing to 
the radial side of the distal extremity of the second, third and fourth 
metacarpals respectively, The fourth tendon, however, has exactly the 
reverse arrangement, passing from the radial side of the fifth meta- 
carpal distally to the distal end of the fourth, and, furthermore, it 
becomes intimately associated with the ulnar (distal) edge of the radial 
profundus slip of the fifth digit. 
The arrangement of the nerve trunks in the reptilian hand is essen- 
tially the same as in the amphibian and does not require any detailed 
description. 
In the preceding account I have refrained from applying to the indi- 
vidual muscles terms borrowed from mammalian myology, because the 
