424 Wortman — Studies of Eocene Mammalia in the 



fragments it can be determined that the ilinm was of good 

 length and considerably expanded anteriorly, as in Mesonyx. 

 The tubercle for the tendon of the rectus is large and rugose. 

 The acetabulum is large, of moderate depth, and the acetabu- 

 lar notch is deeply incised. The ischial spine is distinct, the 

 obturator foramen long and narrow, and the pubis compara- 

 tively short. This latter fact, taken in connection with the 

 narrowness of the sacrum, figure 51, gives a remarkably small 

 outlet to the pelvis. There is, of course, no means of deter- 



50 



Figure 50. — Pelvic outlet of Dromocyon vorax Marsh 

 ing dimensions; one-half natural size. 



51 



anterior view ; show- 



52 



Figures 51, 52.— Sacrum of Dromocyon vorax Marsh, and of a Newfoundland 

 dog ; under view ; showing difference in width ; one-half natural size. 



mining the sex of the fossil ; but assuming it to be a male, if 

 the pelvic outlet in the female were as small in proportion, 

 the young must have been very small at birth. For the sake 

 of comparison, I give in figure 53 an outline drawing of the 



