330 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiii. 



condition of the pelvis, to have been traversed by a large iliac artery. 

 It is a curious fact that in the cared seals the artery may either directly 

 traverse the pu)>is or simply pass through the anterior angle of the 

 obturator foramen, or it may be at tirst free and later on inclosed bj^ 

 bone. There is nothing to determine whether the pelvic halves were 

 attached to the vertebrie or lay free in the flesh, as in the Cetacea, ])ut 

 this last supposition seems the most proba])le. 



The transverse processes of the twenty-second and twenty-third 

 vertebrre difler slightly from those preceding or succeeding them in 

 ])eing a little thicker, rougher, and slightly trihedral at their free 

 extremities; but, unfortunately for the possible deduction that the 

 pelvis was directly attached to either or both of these vertebra, the 

 roughening occurs on the superior face of the process. 



The acetabulum is of good width and depth, exceeding in size that of 

 a male fur seal, Callorkhius, and nearly equaling that of a fully grown 

 female sea lion, Emiietopias. 



There is an irregular, roughened depression, as if for a ligamentum 

 teres, although it is a little difficult to see the necessity for a ligament 

 in so degenerate a pelvis as that under consideration. Moreover, the 

 round ligament is absent (according to Owen) in the eared and earless 

 seals, although both groups have large depressions in the acetabulum. 



Found near the nineteenth vertebra was a small, slender bone sug- 

 gesting a femur, and so considered. There is no articular surface at 

 either end, one extremity, which is slightly weathered, having been 

 apparently' capped with cartilage, the other having lost a portion while 

 being taken away from the matrix. Found near the twenty-second ver- 

 tebra, however, was a rounded fragment of bone of the proper size and 

 shape for a portion of the head of the femur, and if the broken part 

 of the supposed feumr were to be restored after this fragment, it would 

 harmonize with the os, to which it is believed to have belonged. 



If the interpretation placed on this bone be correct, it will be seen 

 that a large third trochanter is present. This, however, need not be 

 considered surprising, since, however distant the relationship may be 

 ))etween Zeuglodon and the seals, it is a relationship that seems to exist, 

 and Scott and Wortman both consider the seals to be descended from 

 the primitive carnivores, through the Creodonts, and these are char- 

 acterized by the presence of a third trochanter on the femur. Also, 

 while it may seem a little singular to iind such a definiteh' formed, 

 though slender, femur present, if it and the pelvis were couipletely 

 buried in the flesh, yet from the great bulk of the tail of Basilosaurufi 

 it appears probable that such was the case. 



It may be said that the last 6 caudals present (the small terminal 

 nodule seems to be lacking) ai-e small, as if embedded in a fluke; that 

 the tenth caudal from the end bears a distinct transverse process, and 



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