SHUFELDT : OSTEOLOGY OF THE STEGANOPODES 193. ,;-' 



being but three sacro-caudals. He says, however, that in this species the general ''' 

 number seems to be forty-two vertebrae in all, not counting the pygostyle. 



In a complete skeleton of Pelecanus fasats before me (No. 18483), I find sixtee^n 

 true cervical vertebrae, none of which support true ribs. The seventeenth bears a 

 pair of large, well-developed ribs which do not connect with the sternum, and which 

 have long epipleural appendages low down on their shafts, where they are anchy- 

 losed. The eighteenth vertebra is the ultimate one of the dorso-cervical series of 

 the spinal column that is free. Its ribs are broad and flat, with their appendages 

 coossified to the shafts at an angle of 45°, and inclined to be slender, narrow, and 

 pointed. 



The nineteenth, twentieth, and twenty-first vertebrae are not only all fused 

 together, but are similarly joined with the bones forming the pelvic "sacrum." 

 This union is most perfect, and is considerably fortified by the complete coossification 

 of the metapophyses extending between the extremities of the transverse processes, 

 and then with anterior iliac borders, in which location the ossifying process has been 

 extended quite across, thus, on superior aspect, shutting the twenty-first vertebra 

 out from view. 



These three vertebrae also bear broad and flat ribs, connecting with the sternum 

 as do all the thoracic ribs in this Pelican. This pair belonging to the nineteenth 

 vertebra are quite like those described above for the eighteenth ; they are broader, 

 however, which is also the case with the pair suspended from the twentieth vertebra. 

 These last have the epipleural spines reduced in size, while the last two pairs of 

 ribs, or those belonging to the twenty-first vertebra, and the pair of "pelvic ribs" 

 lack these appendages entirely. 



Almost completely pneumatic in character, the leading costal ribs are rather short, 

 but the series gMdually increases in length as we pass backwards, all of them being 

 more or less pneumatic, and all being remarkable for having their extremities 

 enlarged, for the purpose of affording a greater articulatory surface at those points. 

 For the most part, the pneumatic foramina in these haemapophyses are to be found 

 at their sternal ends. 



The free pelvic vertebrae all have a swelled appearance, while their surfaces are 

 as a rule smooth, their salient angles much rounded off, and their processes quite 

 subordinated. 



The cup of the atlas is deeply notched above, as is the articular surface of the 

 body behind, concaved upon the same aspect. This surface is of an elongo-reniform 

 outline, its transverse diameter being of the greatest length. A small hypopophysiai 

 tip extends backwards from its mid-point below. 



