THE MUSCULAR SYSTEM. 205 
The semitendinosus is a flat ribbon-like muscle which arises 
from the transverse processes of the anterior caudal vertebra, 
and is inserted by a flat tendon into the inner side of the upper 
part of the tibia. An accessory muscle may join it, after arising 
from the femur, to end upon the surface of the back of the 
crus. 
The semimembranosus is another ribbon-like muscle which 
runs parallel to but beneath the semitendinosus. It arises from 
the outer side of the ischium and is inserted, with the tendon of 
the semitendinosus, into the inner side of the head of the tibia 
by a flat tendon. 
Fig. 160. 
.. tarso-metatarsus, 
Ihalltx.....20... 

Fiexor Tenpons or A PAssEeriIngE Birp. 
The tendon of the fleror longus hallucis crosses superticially to that of 
the flexor profundus digitorum, and then goes to the hallux. The last- 
named muscle exclusively supplies the other three digits. 
The femoro-caudal is a long muscle which springs from the 
transverse processes of the hinder caudal vertebre and is in- 
serted onto the posterior surface of the femur—into its inferior 
trochanter when there is such a process. 
A muscle accessory to this may arise from behind the aceta- 
bulum to join in part the tendon of the femoro-caudal and in 
part to be itself inserted into the femur. 
