236 • transactions. — Zoology. 



ischii, and uncinate process and anterior border of the pubis. It is closely 

 connected with the gracilis. In Iguana Mivart calls this broad sheet 

 sartorius ; Sanders, in Platydactylus, calls the broad sheet sartorius, and 

 the slender gracilis. The fibres of this broad mass converge and pass 

 down the inner side of the thigh to be inserted into the posterior part of 

 the tibia just below the head. Giinther calls this sheet a prolongation of 

 the M. obliquiis abdominis externus. 



A strong broad ligament reaches from the uncinate pubic process to the 

 symphysis ossium ischii. From the under-surface of this ligament, about its 

 middle-third, arises a narrow muscle which is inserted into the middle of 

 posterior surface of the femur. It adducts the leg. It is probably biceps 

 femoris ; but the distinctions of some of these muscles are difficult to make 

 out. The semi-tendinosus and semi-membranosus (?) arise from the tuber 

 ischii, and by a branch from two or more caudal vertebrae, and are inserted 

 into the tibia. These muscles flex the limb, or if that be fixed assist in 

 moving the tail. 



M. obturator externus arises broadly from whole outer face of pubis and 

 ischium, lies in contact with the pubis and ischium, closely covers in much 

 of the hip-joint, and is inserted by a flattened tendon into inner tuberosity 

 of the femur and digital fossa. 



Obtm-ator iuternus arises from ramus and body of pubis, from symphysis 

 pubis, and from uncinate process of pubis, from outer surface of tuber 

 ischii and ramus ischii, and from membrane lining obturator foramen. 

 Ischio-caudal arises by a narrow tendon from the tuber ischii, and is attached 

 to the h^emapophyses of six or seven caudal vertebrae. Internally, it lies 

 against its fellow of the other side, the arms lying between them near their 

 origins. Externally, both are covered by the femoro-caudal, which arises 

 from the sides of the hasmapophyses of several vertebrae ; the thickest fibres 

 arise from the vertebrae nearest the sacrum ; these form a round thick mass. 

 The insertion is very curious. The broad thin layer of fibres coming from 

 the more distant vertebra unite to form a strong glisteniug tendon which 

 passes under the ischio-caudal ligament to the inside of the upper end of 

 the femur. About one-third of an inch from this insertion it gives off a 

 very delicate long branch, which runs down the whole length of the femur 

 in close proximity to the great ischiatic nerve, which it very closely 

 resembles ; it traverses the popliteal space, and is inserted into the back of 

 the fibula. The long slender tendon helps to flex the leg upon the thigh, 

 and acts also on the popliteal fascia. The other tendon would draw the leg 

 backward or move the tail. Giinther thinks it would also rotate the limb 

 outwards ; but this perhaps is not the case, because the tendon at nisertiou 

 so grasps the leg as (possibly) to neutralize any such effort. 



