•462 Annals of the Carnegie Museum. 



the greatly expanded condition of the ihum in this region. The con- 

 striction back of the surface for contact with the sacrum is similar to 

 that in the llama. The peduncle is comparatively long, and the ace- 

 tabulum is deep. The ilium, ischium, and pubis unite to form the 

 acetabulum in much the same manner as in recent forms. The su- 

 perior border of the ischium is high, sharp, and as in the llama, has 

 many small ridges for muscular attachments running from the superior 

 margin across the entire external surface. The posterior portion of 

 the ischium is wanting. The pubis is proportionally short and stout. 

 The shaft is more circular in cross-section than is that of the recent 

 forms. The distal end is narrow, long and thick, instead of broad 

 and short as in living forms. The thyroid foramen is large and ovate 

 in shape. The elongate and narrow pelvis of O. longipes contrasts 

 strongly with the broad and shorter pelvis of the recent species as 

 will appear from the following measurenients of these elements in 

 Oxydactylus longipes and Lama hi/anaco. In the former the width 

 across the pelvis at the acetabular region is 135 ram. while that of the 

 latter is 165 mm., a difference which seems all the more marked when 

 we consider that O. /o/igipcs is on the whole the larger animal of the 

 two. 



The -Femur. — (PI. IX, Fig. 3.) The femur has a comparatively 

 slender sinuous shaft, subcircular in cross-section, greatly expanded 

 both proximally and distally and in general appearance resembling 

 that of the llama. The head is smaller, the ovate pit for the ligamen- 

 tum teres shallower, but its position is the same as in the recent gen- 

 era. The head is separated from the shaft by a longer and more con- 

 stricted neck than in the llama and camel. The great trochanter is 

 higher, not so heavy superiorly, and has not as great an obliquity to 

 the long axis of the bone as in the llama. The bridge from the head 

 to the greater tuberosity being rather short, the digital fossa is accord- 

 ingly narrow laterally, though fully as deep as is that of the llama. 

 The lesser trochanter is a prominent knob unlike the sharp rugose 

 ridge seen in the llama and decidedly more prominent than is that of 

 the camel. At the base of the lesser trochanter there begins a promi- 

 nent ridge for muscular attachment which continues downward on the 

 posterior face of the bone. The same ridge is found in the llama and 

 the camel. The rotular trochlea as well as the condyles are compara- 

 tively narrow, the external condyle being the larger of the two. The 

 intercondylar notch is narrower than in the llama. 



