478 . DR. R. W. SHUFELDT ON [NoV. 16) 



muscle being thin and closely pressed to the pelvis. The fibres 

 converge as they near the femur and terminate in a strong, flat 

 tendon which becomes inserted on the outer aspect of the trochanter 

 of that bone, which insertion is slightly overlapped by the tendon 

 of the gluteus medius muscle. 



The adductors arise from the infero-external margin of the 

 ischium, between the anterior edge of the semimembranosus and the 

 obturator foramen. 



The adductor longus (Plate XLV. fig. 1, a.l) is the more anterior 

 of the two and consequently arises the higher on the pelvis, and 

 comes off in front of the adductor magnus, which it largely overlaps. 

 Its fibres pass obliquely to the posterior aspect of the shaft of the 

 femur, down which they become inserted as far as its middle, along 

 the linea aspera, a line which is well marked in our subject. 



The adductor magnus (Plate XLV. fig. 1, a.m), like the one just 

 described, is also a broad ribbon-like muscle, arising from the ischium 

 between the semimembranosus and a middle point on the underside of 

 the adductor longus, close up to its semitendinous origin. Anteriorly 

 its margin is free, while posteriorly it is juxtaposed to the anterior 

 border of the semimembranosus. Passing parallel with those of the 

 other adductor, its fibres are inserted into the distal moiety of the 

 linea aspera of the femoral shaft, down to the intercondyloid notch 

 of that bone, where this muscle makes a very substantial insertion. 



Removing all the muscles of the thigh thus far described, we find 

 that in this region we have the following ones remaining. They are 

 shown in my drawing (Plate XLV. fig. 2), together with a few as 

 yet undescribed muscles of the leg. 



A very important muscle is the obturator internus (Plate XLV. 

 fig. 2, o.i), and in Geococcyx it exists as we find it in the majority 

 of the class. Prof. Garrod laid some stress on the point whether 

 this muscle arose from a triangular or an oval area. Here it arises 

 from a decidedly oval one, and as usual this is from the mesial sur- 

 faces of the ischium and the post-pubic element of the pelvis. Its 

 tendon emerges from the obturator foramen, and overlapping the 

 gemellus muscle, passes to the outer aspect of the upper part of the 

 trochanter of the femur, where it is inserted. 



The gemellus (Plate XLV. fig. 2, ge) is a short, thick, carneous 

 muscle, which arises about the outer rim of the obturator foramen of 

 the pelvis. Its fibres passing obliquely upwards and forwards are in- 

 serted with the tendon of the obturator internus muscle on the tro- 

 chanter of the femur. This bird also has a few of the fibres of its 

 gemellus muscle inserted into the tendon of the obturator externus 

 muscle, at least I found this to be the case in tlie specimen before me. 



We find the vastus internus (Plate XLV. fig. 2, v.i) to be a strong, 

 fusiform muscle, that is only fully discovered after we have removed 

 the ambiens and the adductors. It lies on the postero-internal aspect 

 of the shaft of the femur, arising from the linea aspera nearly as high 

 up as the head of that bone, and increasing in bulk as it descends, 

 still making attachment to the linea aspera, it only becomes free 

 just above the condyles. At this point it terminates in a flat tendon, 

 which, crossing the articulation of the knee, becomes inserted into the 



