Vol. xv.-j Shufeldt, Osteology of Harris's Cortuoraytt. QQ 



Mesially. the ilia ionii a solid crista the entire length of the hone, 

 which, in the pie-acetahular region, is finished oi^ with a hori- 

 zontally spreading lamina having an average width of some 

 4.5 millimeters. This disappears at a point in advance of the 

 acetahulc-e. and the ilia and " crista " fuse in the same plane. As 

 we pass posteriorly, however, the latter again comes more and 

 more in evidence with its thickened border, until it reaches its 

 maximum height, at its posterior termination, where it is as high 

 as the neural spines of the caudal vertebra;. In the post-acetabular 

 region the mesial margins of the ilia gradually curve away from 

 the sacral crest, which curvature terminates at the place where 

 the mesial margins of the iUa articulate with the transverse 

 processes of the uro-sacral vertebrae (fig. 20). 



There are large interdiapophysial foramina among the last 

 three uro-sacral vertebrae ; but anterior to these such openings 

 become, as a rule, very small. A httle way back of either anti- 

 trochanter, on the dorsal aspect of the pelvis, there is a big, rough 

 elevation for muscular insertion. P. carbo and P. urile ])ossess 

 similar tuberosities on their pelves, while in a number of other 

 kinds of Cormorants they are present, but not especially notice- 

 able. 



Regarding the pelvis of Nannopterum on side view, it is to be 

 observed that a rudimentary prepuhic spine is a character 

 constantly present, and that the cotyloid ritig or acetabulum is very 

 large, as is the massive antitrochanter. As a matter of fact, all 

 this part of the pelvis in Harris's Cormorant is of the most sub- 

 stantial sort, as, indeed, is the entire pelvic structure. 



The ischiac foramen is a very large, elliptical vacuity, and, 

 being so large, tends to hghten greatly the pelvis as a whole. So, 

 too, we find the obturator foramen of good size and almost con- 

 tinuous with the obturator space, which latter is a vacuity nearly as 

 large as the ischiac foramen. Posterior to it there is a broad, 

 fiat area of bone, formed about equally of the ischium and ilium, 

 the free, moderately sharp border of the former being deeply 

 convex outward. The pubic element or style articulates here, 

 broadening as we follow it backward, then thickening, turning 

 very abmptly toward the mesial plane, and terminating with an 

 expanded tip. 



Where this pubic element bounds the obturator space below, 

 however, it is a very slender and long rod of bone — in fact, 

 slightly slenderer than" the quadrato-jugal arch of the skull, and 

 no stronger than the lower part of the fibula in the leg. 



A very deep, triangular notch indents the posterior border of 

 the pelvis, it being the iho-ischiac notch, and is characteristic of 

 the pelves in the PhalacrocoracidcB generally. It results in con- 

 verting the hindermost extension of the ihum into a long, strong, 

 backward-directed, straight process, which, with the aid of the 

 corresponding process of the other side, furnishes great protection 

 to the leading caudal vertebrae. (See figs. 18, 19, and 20 of 

 Plate XVIII.) 



