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Show 86 MR. A. SANDERS ON THE [Jan. 6, Gluteus maximus (fig. 5, Gl. Mx.) is more distinct from the rectus than in L. belli, and still more so than in P. japonicum. It arises from the whole length of the posterior apophysis of the ilium, and joins the vastus externus at about the centre of the thigh. This is the same as gluteus maximus in Iguana, but not in the Chameleon. Biceps femoris (fig. 5, B.F.) arises from near the posterior end of the posterior apophysis of the ilium by means of a narrow tendon, and, passing down the thigh, is inserted into the outer side of the fibula a short distance beyond the head of the bone ; its tendon is crossed by that of the peronaeus ; this corresponds to the ilio-peroneal in Iguana. Semimembranosus (figs. 5 & 6, Sm.) arises fleshy from the posteroexternal angle of the ischium and from the ventral end of the ilio-ischiatic ligament; its belly forms an elongated cone, which becomes at the distal half of the thigh a long thin tendon, which receives the tendon of the pelvo-tibialis, and is inserted into the outer edge of the head of the tibia, passing through the knee-joint on its way. ^ In this species the semimembranosus of L. belli and the principal section of that muscle in P. japonicum appear to be absent; but this muscle would seem to represent that section of the semimembranosus which in P. japonicum was inserted between the tibia and fibula, close to the insertion of the pelvo-tibialis, and corresponds to the second portion of the semimembranosus in Iguana. Semitendinosus (figs. 5 & 6, St.) arises immediately behind the last, from the posterior part of the ilio-ischiatic ligament, extending nearly as far as the posterior end of the ilium. It ends in a long thin tendon, which is inserted into the external edge of the head of the tibia close to the insertion of the pelvo-tibialis ; it also gives off two supplementary tendons, one of which goes to the inner side of the tibia, close to the insertion of the gracilis, the other goes down the leg along the inner edge of the soleus; this clearly corresponds to the biceps in Iguana. I am still of opinion that the interpretation of these three muscles is in the main correct. With regard to their origins they maintain the relations found in the human subject (semimembranosus arising ventrad of the others) both in the present specimen and in L. belli and P. japonicum, where, moreover, the two latter muscles are inserted into the inner side of the head of the tibia. With regard to the ilio-peroneal, both its origin and insertion appear to me to agree very well with those points in the biceps; and Prof. Rolleston in the memoir above referred to remarks that " this muscle is clearly one of the series made up of the biceps &c," which opinion might perhaps justify me in adhering to m y former interpretation. Gluteus medius (fig. 5, Gl. Md.) arises fleshy from the outer side of the anterior two thirds of the ilium, covered by the gluteus maximus, and is inserted into the outer and posterior side of the femur for nearly half its extent beyond the head and behind the origin of the vastus externus. Quadratus femoris (fig. 5, Q.F.) arises from the posterior point of the ilium behind the biceps femoris and in front of the semitendinosus ; it is inserted into the proximal end of the femur dorsad of the insertion of the pyriformis. |
