SHUFELDT : OSTEOLOGY OF THE STEGANOPODES 197 



The obturator foramen merges completely with the obturator space, which latter is 

 large and broadly spindle-form in outline. No prepubis is present, and the post- 

 pubic style is curved and very slender until it comes in contact at a point on the 

 postero- ventral angle of the ischium, after which it is turned slightly mesiad and 

 somewhat though not at all greatly enlarged. 



An extensive, subelliptical ischiadic foramen monopolizes much space on this lat- 

 eral aspect of the pelvis. Behind it the surface of the bone is smooth, and finally 

 we notice a broad, shallow notch on the posterior border, between ilium and ischium. 

 Dorsad, the pelvis is broad, smooth and flat, with a thorough fusing of all the bones 

 composing it. Parial foramina occur between the diapophyses of the uro-sacral ver- 

 tebrae only in the post-acetabular region, where they are of good size. 



The ultimate vertebra may be more or less individually outlined, and simulate 

 in form the leading one of the caudal series. In the pre-acetabular region the ilia 

 are moderately concaved, lie more or less in the horizontal plane, and fail to come 

 quite in contact with each other over the "sacral crista," which latter is here quite 

 low and indistinct, due to the thorough fusing of all the bones in this region. From 

 the extreme outer point of one antitrochanter to the corresponding point on the 

 same process on the other side measures, on a right line, about 7.5 cm., while the 

 length of the "pelvic sacrum" is about 12 cm. 



Thus, though steganopodous in character, this pelvis of Pelecanus differs mate- 

 rially in form and aspect from the pelvis of either a Cormorant or an Anhinga. 



In the skeleton of the tail we find six free caudal vertebrae and a large pygostyle. 

 All are highly pneumatic. The neural canal, of some considerable size, passes 

 through the entire series and well into the pygostyle — an unusual occurrence in 

 birds. All possess tuberous neural spines, but only the last three have haemal ones, 

 and these increase in size from the last caudal to include the fourth. They extend 

 almost directly forwards. The transverse processes of the first five vertebrae are 

 bent ventral-wise, more particularly in the second and third, while in the last one 

 they are nearly aborted. The articular facets on the centra are concaved anteriorly, 

 and nearly flat on the posterior aspects. 



The large pygostyle is drawn out into a blunt point at its postero-superior angle. 

 Its dorsal margin and the hinder half or more of its ventral margin are sharp — the 

 remainder of the latter being thickened. The antero-inferior angle projects forwards, 

 corresponding to the haemal spine of the first vertebra absorbed to form this com- 

 pounded bone. 



Thus it will be seen that in this species of Pelican we have 41 vertebrae in its 

 spinal column, namely : sixteen cervicals that are without free ribs ; one cervical with 



