} J. Playfair MceMurrich 471 
terminal slips are recognizable, the ulnar one is very small, the main 
insertion of the muscle being into the radial side of the digit. It may 
be noted also that in Iguana this fifth portion at its origin overlaps 
somewhat the fourth portion, an arrangement which is, however, by 
no means so pronounced in Callisaurus or Liolepisma. 
The second portion which passes to the fifth digit (Figs. 4 and 5, 
ab. m.) may well be termed the abductor minimi digitt. It is through- 
out its extent quite separate from the rest of the superficial sheét, 
except immediately at its origin which is from the ulnar prolongation 
of the line from which the rest of the flexor superficialis arises. In the 
Iguana the muscle wraps itself around the fifth metacarpal to a con- 
Fic. 5. The flexores breves profundi and intermetacarpales of Jguana. abm, abductor 
minimi digiti; fbpq, direct and fbp,, oblique muscles of the flexor profundus; im, 
intermetacarpales; fbm,,, line of origin of the stratum medium of the flexor brevis 
medius; p, deep palmar aponeurosis which gives origin to the profundus tendons; 
ve, volar cartilage. 
siderable extent, but in Callisaurus this is not so evident, the muscle 
lying rather to the ulnar side of the bone, but in both it is inserted 
into the ulnar side of the proximal phalanx of the digit. The muscle 
is more or less closely related to one of the slips of the flexor brevis 
profundus (Fig. 5, fbp>) and might on this account be regarded as pos- 
sibly a portion of that layer rather than of the superficialis. I shall 
postpone a discussion of this possibility until the profundus layer has 
been described. 
The stratum profundum of the superficial flexor I did not succeed 
in tracing perfectly in Iguana, a large slip passing to the fourth digit 
and a smaller one to the third being the only portions observed. In 
Callisaurus and Liolepisma, however, it was readily distinguished in 
