=u 
J. Playfair McMurrich 413 
and a stratum profunduf. The stratum superficiale (Fig. 4, fbs), takes 
its origin from the sesamoid bone developed in the tendon of the crural 
plantaris profundus II-III, and, therefore, from a portion of the super- 
ficial aponeurosis. In Scincus it forms a continuous sheet, lying at first 
to the medial side, of the terminal portion of the plantaris superficialis 
lateralis and resting directly on the continuation of the tendon of the 
plantaris profundus II-III. As this tendon divides into slips for the five 
digits, the flexor superficialis divides into corresponding portions, each of 
these, as a rule, again dividing into two slips, which insert into either side 
of the base of the proximal phalanx, the tendon of the plantaris profundus 
II-III passing between them. The slip to the hallux could not be traced 
se 
Fic. 4. Transverse section through the foot of Scincus near the heads of 
the second metatarsal. fbm, —flexor brevis medius str. profundum; fom, = 
flexor brevis medius str. superficiale; fbp, and fop,—fibular and tibial slips 
of flexor brevis profundus; fbs, — flexor brevis superficialis str. profundum; 
fbss = flexor brevis superficialis str. superficiale; im—<intermetatarsal liga- 
ments; pa, and pa, —deep and superficial layers of the plantar aponeurosis; 
II-IV = metatarsals. 
to the phalanx, but faded out over the tendon of the plantaris before 
reaching the metatarso-phalangeal joint. 
In Iguana the muscle, though well developed, is limited in its insertion 
to the three tibial digits, the slip for the hallux early separating from the 
rest of the muscle and no slips passing to either the fourth or the fifth 
digit. 
In addition to the flexor brevis superficialis the abductor quinti digiti 
(Fig. 3, ab°) is probably to be assigned to the superficial plantar layer. 
In Scincus it is a small muscle which arises from the surface of a strong 
ligament extending from the fibular surface of the proximal tarsal bone to 
the base of the fifth metatarsal. As was the case with the corresponding 
muscle in the urodeles, its assignment to the superficial plantar Jayer is 
not beyond question, although it is indicated by the position of the muscle 
