Proceedings of the Scientific Meetings of the Zoological Society of London 1890

Page 238

188 DR. R. Vi. 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 arc here repre­sented 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 pro­jecting 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, where 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 inser­tion is the internal head of the gastrocnemius inclined to be at all tendinous. W e find the round cord formed by the fusion of the tendons of the pyriformis and the auxiliary tendon of the femoro­caudal inserted into the tendon of origin of the external head of the gastrocnemius a few millimetres below the point from whence it arises, A very long and strong internal lateral ligament 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 common 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.