122 The Alligator and Its Allies 
II. This is a more anterior and inner muscle, 
small in size, which has a fleshy origin from the 
bodies and ribs (transverse processes) of the second 
sacral and first caudal vertebree at a distance from 
the posteromedian border of the ischium. It 
extends caudad, lying near the hinder part of the 
pubi-ischio-femoralis externus, and is inserted 
on the trochanter. 
Flexor Tibialis Externus (Plate III., Figs. 1, 2, 
3, fl. tb: ext. or f. t. ext., Plate IV., Fig. 4, fl. tb. 
ext., Plate V., Figs. 1 and 3, fl. tb. ext. and f. t. 
ext.) (Triceps flexor cruris partim, Biceps). A 
strong, spindle-shaped muscle that arises, together 
with the ilio-fibularis, by a short tendon, from the 
side of the portio dorsalis of the ilium, and in 
the neighborhood of the bend of the knee is split 
into two tendons, of which the short one is inserted 
on the fibular side of the neck of the tibia, while 
the other, running along near the caput femoris of 
the gastrocnemius muscle, unites with the tendon 
of the caput tibie of the gastrocnemius muscle 
just beyond the ankle joint. 
Flexor Tibialis Internus (Plate III., Figs. 1, 2, 3, 
fi, th. 1nt., ort, t. 4t., Plate TV., Fig. 4, dl. tb. int. 
Plate V., Fig. 1, fl. tb. int.) (Demi-nerveux+ 
Demi-membraneux, Triceps flexor cruris partim, 
Gracilis, Adductor flexor tibialis, Semimembrano- 
sus, Semitendinosus+Gracilis partim, Gracilis+ 
Semimembranosus + Semitendinosus). A three- 
headed muscle whose heads arise separately and 
