SHUFELDT : OSTEOLOGY OF THE STEGANOPODES 169 



pointed extremity." But I am inclined to think that the vomerine ossification is 

 not always a constant character in these birds. Ossifications of the eyes, ears and 

 tongue agree in the main with the corresponding parts in the Anhingidx, and have 

 been more or less fully described above. 



V-shaped in pattern, the mandible is a strong bone in birds of this family. This 

 is due to the thickness of the rami, and not to their height, for they are rather low 

 than otherwise ; also to the unusual firmness of the dentary ossification with the 

 other bones posterior to it, and finally to the total absence of a ramal vacuity — 

 the mandible not being weakened at those points (see Plate XXIV., Fig. 17). Each 

 dentary upon its mesial aspect shows a deep longitudinal groove. The articular 

 ends are truncated posteriorly, though the postero-mesial angles are somewhat pro- 

 duced. Each of these articular cups appears to be connected with iits respective 

 ramus by a kind of neck, which is directed backwards and towards the median line. 

 When seen from above, and the jaw is articulated in situ, this gives rise to rather 

 an odd-appearing articulation. Either quadrate is thus entirely shut out of sight, 

 with the exception of its externo-lateral process, the base of which does not come 

 in contact with the mandible at all. The sides of the rami are ivithin the quadrato- 

 jugal bars, and rise somewhat above them. The pterygoids, owing to a special 

 notch in each articular cup, are thoroughly exposed, but no more. 



Of the Remainder of the Axial Skeleton. — Seventeen vertebrae are found in the 

 cervical region of P. urile, before we arrive at one that bears a free pair of ribs. A 

 small pair of rudimentary ones in this species are to be observed in the eighteenth 

 vertebra. Now in P. urile these last are not liberated, while in the nineteenth and 

 twentieth vertebrae the free ribs are long, well developed, and have anchylosed upon 

 them large unciform processes. In the leading pair, however, either upon one side 

 or the other, this last character may be absent. Such is the case on the left side 

 of the specimen at my hand. 



P. urile has its entire vertebral chain in many respects quite different from any- 

 thing we described for Anhinga. We do not meet with the greatly elongated eight 

 leading cervicals, and the abrupt change in character as we pass to the ninth one. 

 Nothing of the kind occurs in the Cormorant, for in it the eight leading cervicals 

 are quite in harmonic proportions in all respects with those that follow them. We 

 nevertheless find in this Cormorant the same modifications, only in a far less marked 

 degree, in the eighth, ninth and tenth vertebrae, which give this bird the power to 

 draw back its head and with great rapidity to thrust it forward again, the point of 

 flexure being between the vertebrae just mentioned. Anhingas catch all the fish 

 they eat by spearing them with their sharp beaks while in active pursuit under 



