EMERSON: ANATOMY OF TYPHLOMOLGE. 
67 
crista muscularis of the pubo-ischium. It tapers rapidly, the distal 
two thirds being very slender, and inserts on the outer surface of 
the proximal end of the tibia. 
The semimembranosus (ischio-flexor), a long slender muscle 
arising from the postero-lateral angle of the pubo-ischium, is 
covered by the semitendinosus at its origin and inserts ventral 
to it on the proximal end of the tibia. 
The pubo-tibialis, a very slender spindle-shaped muscle, arises 
from the antero-lateral angle of the pubo-ischium and inserts dorsal 
to the semitendinosus. 
These three muscles serve as flexors of the hind limb. 
The ischio-cauclalis is a thick and rather broad muscle arising 
from the posterior border of the pubo-ischium and uniting with 
the lateral caudal muscle mass at the second myocomma posterior 
to the cloacal orifice. 
The caudali-pubo-ischio-tibialis, a long and very slender muscle, 
arises with piriformis (caudali-femoralis) from the fifth or sixth 
caudal vertebra and is covered posterior to the cloacal orifice by 
the ischio-caudalis. Its fibers join those of the semitendinosus on 
the inner surface of that muscle, near the postero-lateral angle of 
the pubo-ischium. 
These two muscles are flexors of the tail, hence the attachment 
of caudali-pubo-ischio-tibialis to the caudal vertebrae, described 
above as its origin, is physiologically its insertion. 
Deep layer. — The pectineus (pubo-ischio-femoralis externus), a 
broad thick sheet, arises from the whole length of the crista mus¬ 
cularis of the pubo-ischium, covered posteriorly by semitendinosus, 
and tapers rapidly to its insertion on the outer surface of the tro¬ 
chanter of the femur. Anteriorly it covers the insertion of the 
rectus abdominis. 
The adductor (pubo-ischio-femoralis interims), a thin, delicate, 
narrow sheet, arises from the antero-lateral portion of the dorsal 
surface of the pubo-ischium. Emerging, it passes over the head 
of the femur and inserts on the proximal fourth of its outer sur¬ 
face, dorsal to pectineus. 
The quadratus femoris (ischio femoralis) is*a very short and thick 
muscle covered by pectineus, arising from the postero-lateral angle 
of the pubo-ischium and inserting on the ventral part of the trochan¬ 
ter of the femur. 
