186".] MYOLOGY OF IGUANA TUBERCIILATA. 793 



Fi.2. 17. 



Deepest muscles of right thigh ; ventral aspect. The gracilis is entirely removed. 

 The tibial adductor, the semimembranosus, and the adductor magnus are 

 cut short and reflected. 



A. Adductor magnus. B. F. Biceps femoris. C. Crureus. F. C. Femoro- 

 caudal. Go. I. Grastrocnemius internns. LP. Ilio-peroneal. 0. E. Ob- 

 turator externus. 0. 1. Obturator intern us. Pc. 1-3. Pectineus. Pf. Pj- 

 riformis. B. F. Rectus femoris. iS'. Tibial adductor. S. M. Semimem- 

 branosus. S. T. Semitendinosus. V. I. Vastus internus. y. Tendon of 

 insertion of feraoro-caudal given off from the larger tendon and going to 

 the popliteal space. 



Obturator externus*. This is very fleshy, and arises from the 

 ischium and the outside of the obturator membrane (fig. 17, O.E.). 

 It is inserted into the trochanteric fossa immediately above the sum- 

 mit of the insertions of the gluteus medius and pyriformis. 



The obturator internusf (fig. 1 7, O. /.) arises from the posterior 

 part of the deep surface of the ischium. Curving round the outer 

 margin of that bone (between the acetabulum and the tuberosity), it 

 is inserted, by an exceedingly strong tendon, into a pit on the outer 

 side of the articular head of the femur. 



Pyriformis (figs. 15 & \7,Pf.). This muscle J arises from the 

 under surfaces of the first four caudal transverse processes, between 

 the large femoro-caudal muscle on the inside and the conjoined in- 

 sertions of the two median series of lateral caudal cones on the out- 

 side. It is inserted into the strong tendinous arch passing from the 

 ilium to the pubis and enclosing the tendon of the femoro-caudal 

 muscle. Thence taking fresh origin, and accompanied by an ante- 

 rior fasciculus coming direct from the caudal vertebrae, it is finally 



* This appears to answer to the m. quadrafus femoris of Stannius (p. 134. 

 no. 10). 



t The obturator internns of Stannius {loc. cit, p. 134. no. 5) is a part of my 

 iliacus. 



\ It is the m. sjihcaudaUs of Stannius {Joe. cit. p. 133. no. 4). 



Proc. Zool. Soc. — 1867, No. LI. 



