188 DR. R. W. SHUFELDT ON [Apr. 1, 



this locality being nearly opposite each other. When the femur is 

 articulated in situ these insertions of the obturators look to the outer 

 side. 



Muscles of the Leg and Foot. 



101. Gastrocnemius. — Both heads of this muscle are here repre- 

 sented and strongly defined. The external head arises by a long, 

 cord-like tendon from the outer aspect of the external condyle of 

 the femur, and passing directly down the back of the leg, parallel to 

 the shaft of the fibula, it becomes fleshy at the upper third of the 

 leg and, forming a flat, thin, and rather broad muscle, goes to the 

 tarsus for its insertion. It is inserted into that prominently pro- 

 jecting ossicle of the distal row of tarsal bones, nearly in line with 

 the fibula. 



The internal head of the gastrocnemius arises from the proximal 

 third of the outer side of the shaft of the tibia, and passes obliquely 

 across the back of the leg, wliere it is seen to be a broad, thin, and 

 conspicuous muscle. It is inserted into the mesial edge of the belly 

 of the external head of the muscle we have under consideration, a 

 short distance above its insertion. At neither its origin nor its inser- 

 tion is the internal head of the gastrocnemius inclined to be at all 

 tendinous. ^Ve find the round cord formed by the fusion of the 

 tendons of the j)yriformis and the auxiliary tendon of the femoro- 

 caudal inserted into the tendon of origin of the external head of the 

 ffastrocnemius a few millimetres below the point from whence it 

 arises. A very long and strong internal lateral hgament of the 

 knee-joint is found in Heloderma, and it can be examined just above 

 the origin of the internal head of the gastrocnemius, but it in no 

 way overlaps the latter as Mivart states to be the case in Parson's 

 Chameleon. 



102. A Soleus is here but very feebly developed, consisting of 

 only a few fibres and withal intimately attached to the inner surface 

 of the external head of the gastrocnemius. It arises from the back 

 of the tibia at its proximal end, and is inserted in connnon with the 

 tendon of the gastrocnemius into one of the ossicles of the distal 

 row of the tarsus. The internal margin of the soleus muscle is 

 re-enforced by a tendon which is sent down by the semitendinosus 

 muscle of the thigh. 



103. Peroneus secundus. — This muscle arises from the antero- 

 external aspect of the fibula, from a point corresponding to the 

 insertion of the biceps to within a short distance of the external 

 malleolus. Beyond this it forms a tendon, which^ passing to the 

 tarsus, becomes inserted into that bone that has been designated by 

 Sanders as the " cuboid." Comparatively large and thick at its 

 lower portion, it here gives off a fascia which, spreading over the 

 back of the tarsus, is so attached that it forms a binder to hold in 

 place the flexor tendons passing beneath it ; above, it is closely 

 associated with the biceps, the tendinous portion of its origin 

 being just anterior to the tendinous portion of the insertion of the 

 latter. 



