1867.] myology of iguana tu bkkculata. 7s7 



Muscles of the Pelvic Limp. 



Psoas and lUacus. I am inclined to regard the complex muscular 

 mass which goes from the inside of the pelvis, passing over its brim 

 to the femur, as the homologue of the psoas and iliacus. I find 

 present four muscular bundles. The first (figs. 13, 14 & 16,/. 1) 

 arises inside the pubis, from a median raphe separating it from its 

 fellow of the opposite side and also takes origin from the most ven- 

 tral portion of the pubis, overlapping its brim. Its upper (or pos- 

 terior) margin is conterminous with the inferior (or anterior) margin 

 of the second part of the muscle, and lies superficially to the third 

 part. Passing over the brim of the pelvis, above the spine of the 

 pubis, it is inserted into the tendinous arch going from the front of 

 the acetabulum to the symphysis ischii, and into the upper half of 

 that part of it which is between the acetabulum and the spine of the 

 pubis. It is intimately connected with the second and third parts 

 of this complex muscle and with the tibial adductor. 



The second part of the muscle (figs. 13, 1-1 & 16, /. 2) lies above 

 (z. e. nearer the vertebral column than) the first part. It arises also 

 inside the pelvis, from a median raphe which separates it from its 

 fellow of the opposite side. It is inserted in common with the third 

 portion, and is indeed, in part, only with some difficulty separable 

 from the first portion, with the upper (or posterior) margin of which 

 its lower (or anterior) margin is conterminous. 



The third portion is a very broad muscular layer, which lies hidden 

 by the first and second portions of the muscle. It arises from the 

 internal surface of the pubis, ischium, and obturator foramen ; and 

 the upper (or posterior) part of its origin is easily separable from 

 the more ventral (or anterior) portion. It is inserted into the tibial 

 side of the upper part of the shaft of the femur, internally to the 

 sumiuit of the crureus, just above the insertion of the adductor, and 

 slightly overlapping the tendon of insertion of the femoro-caudal. 

 It is, however, mainly inserted by a strong tendon, which passes 

 across the front of the upper end of the shaft of the femur, beneath 

 the summit of the vastus externus, to the insertion of the gluteus 

 medius, which slightly overlaps it. Thus, the tendinous insertion 

 being on the peroneal side of the bone, while the muscular fibres 

 (inserted with those of the two preceding portions of the iliacus) are 

 attached rather to the tibial side, the upper part of the femur 

 comes to be more or less embraced. 



The fourth and smallest portion of the complex muscle (fig. 16, 

 /. 4) springs from the surface of that upper (or more posterior) 

 division of the origin of the third part already spoken of (namely 

 that division of the third which arises from the ischium and obtu- 

 rator membrane, and which might be called a fifth portion), and lies 

 nearer the vertebral column than do the other parts. It is inserted 

 in common with the muscular insertion of the third part of the 

 muscle just described ; but its fibres are partly continuous with those 

 of the crureus, crossing over tlie tendon of insertion of the third 

 part of the psoas and iliacus. 



