196 MEMOIRS OF THE CARNEGIE MUSEUM 



The prezygapophysial facets are long, narrow and ellipsoidal in form on the 

 third cervical, being considerably nearer each other at their posterior ends than they 

 are in front. They face almost directly dorsad. As we pass to include the seventh 

 cervical these facets gradually become more and more circular in outline, and incline 

 to face towards the median plane. This they do quite abruptly in the eighth 

 cervical distinctly so in the ninth, look slightly backwards in the tenth, but 

 again thereafter gradually right themselves so as to once more face the median 

 plane. Here it will be seen we have the same arrangement noted for the Cormor- 

 ant and the Anhinga though not nearly so well marked. The postzygapophyses 

 are short and stumpy in the fourth vertebra, but very gradually lengthen to include 

 the twelfth cervical, after which they once more shorten, to become short and 

 thick-set again in the last cervicals, and the free dorsal, in which last as distinct 

 processes they are practically aborted. Their facets for articulation with the cor- 

 responding ones on the prezygapophyses, are upon their ventral aspects, and of 

 course have an exact counter-facing to them. 



These vertebras commence to lengthen after passing the third cervical, becoming 

 quite longish and narrow in mid-series they then very gradually assume the 

 broad, massive, and short type found at the end of the cervical chain and in the 

 free dorsal. Though these latter are large they agree with all the others of the 

 column, from their extreme pneumaticity, in being very light in weight. 



The three last dorsal vertebrae coossify, or rather in the adult Pelican are fused 

 with those of the pelvic sacrum, and the leading vertebra of the latter is quite 

 similar to one of the last dorsals, but in the next three the parapophysial processes 

 are thrown up against and completely fused with the ventral surfaces of the ilia 

 upon either side. These processes are spine-like and nearly aborted in the next 

 following one, while in the next three they are absent entirely. This is well shown 

 in the pelvis of Pelecanus sharpei (PI. XXX., Fig. 49). 



Then comes a true sacral vertebra, which has them long and well-developed, 

 reaching out to points posterior to the acetabute where they fuse and broaden, and 

 otherwise develop bone which greatly strengthens the pelvis in all this vicinity. 

 The five remaining vertebrae of the "pelvic sacrum" also possess parapophysial proc- 

 esses, which with the diapophyses above them, most completely coossify with the 

 internal borders of the ilia upon either hand. Of good capacity, the " pelvic basin " 

 is of a short, oblong form, being one third narrower than it is long, and of nearly 

 uniform depth throughout. Viewed laterally, we find the acetabulum to be large 

 and circular; its internal periphery coequal with its external one. Above it is a 

 fair-sized antitrochanter, facing forward and downward, and very slightly outward. 



