74 ProceecU7ig8 of the Royal Irish Academy. 



In the hind limb : — 



Sartorius consists of two parts, primus and secundus ; the 

 former arises from the anterior superior spine of the ilium, and by a 

 few fibres from the abdominal parietes, and is inserted into the 

 inner side of the femur for the third one-fourth of its length ; it is sup- 

 plied by the external cutaneous nerve of the lumbar plexus. Secundus 

 arises from the middle of Poupart's ligament and from the abdominal 

 wall, and runs to the upper point of quadrisection of the tibia. This 

 latter portion was not found at all by Professor Humphry, though his 

 description of the former division agrees closely with the above arrange- 

 ment. In Bradypus and Arctopithecus there is but a single origin, 

 which, however, takes in both the parts above mentioned (ilium and 

 Poupart's ligament), but the insertion is double, into femur and tibia, 

 though the latter insertion did not exist in Professor Macalister's 

 specimen. 



Psoas parvus presents nothing remarkable, arising from the five 

 lower dorsal vertebrge, and being inserted into the pectineal tubercle. 



Psoas magnus is separable with difficulty from the normal Iliacus, 

 and has a coextensive origin with psoas parvus. 



Pectineus stretches from the pectineal tubercle to the upper half of 

 the femur. The arrangements in Professor Humphry's specimen are 

 substantially the same as these. 



The three adductors are also normal and correspondingly arranged, 

 primus being quite separate, secundus not divisible into two laminae, and 

 inserted into the middle of the femur, and tertius, extending from the 

 horizontal ramus of the pubis to the lower point of trisection of the 

 femur, or to the condyle, as in Professor Humphry's specimen. 



Quadratus femoris is normal, agitator caudae absent, as is the case 

 also with obturator internus, but its non-appearance is compensated 

 for by obturator externus, which consists of two parts, the upper aris- 

 ing from the horizontal ramus of the pubis near the acetabulum, the 

 lower, which is penniform, taking origin from the whole obturator mem- 

 brane, and both the inside and outside of the horizontal ramus of the 

 pubis. 



The gemelli are present and distinct.* Glutseus maximus is a fan- 

 shaped muscle arising from the fascia over the side of the sacrum and 

 of glutseus medius, and from the tuber ischii ; it is inserted half way 

 down the outside of the femur. 



Pyriformis is very separate, arising from the front of the sacrum 

 inside the pelvis, and inserted into the great trochanter, fused with 

 that of glutaeus medius, which arises as usual from the iliac fossa, and 

 is overlapped by glutasus quartus both at origin and insertion. 



Glutseus minimus exists as a very fine band crossing the back of 

 the capsule of the hip joint, from the margin of the acetabulum to 

 the great trochanter, underneath pj-riformis. . Glutseus quintus is 



* There was a doulilc obturator extern\is in Arctopithecus, but a single one in 

 Bradypus. 



