50 Field Columbian Museum — Geology, Vol. II. 



looking upward; and a small one looking forward and a little down- 

 ward for the pubis. The anterior border is concave, and the portion 

 adjacent to this border is the thickest of the bone. The symphysial 

 border is thickened on the anterior third, gradually thinning posteriorly. 

 This border is obliquely truncated, as in the pubis, anteriorly; poste- 

 riorly the cartilaginous border, moderately thin, is continued around 

 .the inner angle to the outer one, where it meets the free outer border 

 abruptly. The outer border is gently concave in its whole extent, 

 and only a little thicker than the inner portion of the bone. It ends 

 in a right angle. (PI. XVII.) 



The ilium is a small, rod-like bone, moderately expanded at its 

 ischial extremity. Of the two articulating extremities, that for the 

 ischium is much larger than the one for the acetabulum. In the 

 middle of the bone, a cross-section is roundly oval. The upper 

 extremity has a small, flattened, parallelogrammatic surface, which, 

 in the articulated pelvis, looks inward, slightly backward, and 

 perhaps a little downward. The bone when articulated was directed 

 backward at an angle of about thirty degrees, and inward perhaps a 

 little more. There is very little evidence of articulation with the 

 sacral ribs. The union must have been weak and slight. 



The pelvis, as a whole, was troughlike, as was the pectoral girdle. 

 The two bones meet at a considerable angle, and it is also certain 

 that there was a large angle between the ischium and pubis, so that, 

 with the ischial symphysis nearly horizontal, the pubes were directed 

 at a considerable angle downward. This position, indeed, is necessary, 

 since otherwise there would have been a strongly upward turn of the 

 abdominal contour immediately behind the coracoids, and the ischia 

 and pubes will articulate in this position only in this specimen. 



Front Limbs. — The paddle-bones of the specimen were all com- 

 pletely intermingled and displaced, so that none could be referred to 

 its proper limb from the position they were in. 



Apparently nearly all were preserved, though some of them were 

 distorted and crushed. The labor of assorting and correctly locating 

 these parts was very great, especially the phalanges; indeed, of the 

 latter there is little assurance that the final collocation in many cases 

 is correct. Aside from the femora and humeri, the only distinction 

 that could be made between the bones of the front and hind limbs 

 was in the size, always slightly smaller in the hind than in the fore 

 limb. By thus assorting into pairs and assigning the smaller pair to 

 the hind limb it was certain that the bones of the epipodial and meso- 

 oodial regions were correctly placed. The labor was much lightened 



