1 96 SHUPELDT. 



THE SKELETON OF THE PELVIC LIMB. 



Proportionately^ the pelvic limli of Cynoccplialus is not as powerfully 

 developed as is the pectoral liml), though there seem to be exceptions to 

 this general rule. In Steere's specimen, for example, the long bones of 

 the posterior limbs are fully as well developed as are the corresponding 

 ones in the anterior extremities. However, pes always seems to be weaker 

 and somewhat smaller than manus, and this is also evidenced in the 

 skeleton of these parts. 



In the matter of proportions there are very marked differences in the 

 pelvic limbs of the three skeletons at hand. These differences may be 

 due to the fact tha.t they came from different species, or if from the same 

 species, it may be due to differences in age or even sex. In any event 

 the Steere specimen was a much bigger animal than either of the 

 McGregor specimens, and one of the latter (3) is larger than the other 

 (2), though the characters throughout agi-ee. 



Two of the femora, selected as examples, show how marked these 

 differences are; for instance, the right femur of the Steere skeleton has 

 an extreme length of 13.3 centimeters, as compared with the extreme 

 length of the fenmr in the smaller of the two individuals from the Bureau 

 of Science, which is only 11.1 centimeters. Then in the matter of actual 

 size the two bones are also in j)roportion to this difference in length, 

 the shaft of the femur in the first case being fully one-third larger than 

 in the second case. 



The description of the pelvic limb here given is from the light side 

 of the skeleton in Steere's specimen, witli occasional reference to the 

 other two individuals. 



The femur (Plate II, figure 6), possesses a stout, straight, cylindrical 

 shaft, which is so smooth that even linea aspera is scarcely indicated 

 upon it. The proximal extremity of the bone presents an elegant, smooth, 

 hemispherical head, in fact so globular is it that it approaches the sphere. 

 This head is marked by no pit for the ligamentum teres; its boundary 

 is sharply defined in front; less so behind, where the articular surface 

 encroaches slightly upon the summit of the shaft of the bone. The axis 

 of the head and neck makes an obtuse angle with the axis of the shaft, 

 thus bringing the head above the latter's summit. Conspicuous and 

 rough, the great trochanter curves slightly to the front, thus making the 

 neck of the bone very distinct behind it and the caput femuris. Minute 

 nutrient foramina may occur in this locality. On the postero-external 

 aspect of the great trochanter there is a well-marked pit, the so-called 

 trochanteric fossa, within which certain muscles are inserted. 



Situated internally and at the same tmie posteriorly, and about 1 centi- 

 meter below the head, there arises the lesser trochanter, sometimes called 

 the tibial trochanter. It is bluntly triangular in form, and arises from 

 a substantial base. On the opposite side of the shaft, that is, on its 



