SHUFELDT : OSTEOLOGY OF THE STEGANOPODES 



221 



PLATE XXIII. Fig. 10. Superior aspect of the skull of Sula tjossi. Mandible removed. Same 



specimen as the one shown in Plate II., Fig. 8. Very slightly reduced. 

 Fig. 11. Superior aspect of the skull of Sula brewsteri. Mandible removed. 

 Same specimen as the one shown in Plate II., Fig. 9. Very slightly reduced, 

 and in the same proportion as the skull shown in Fig. 10. 



Fig. 12. Left lateral view of the trunk skeleton of Sula gossi. Reduced one 

 third. Belonged to the same individual, which furnished the skull shown in 

 Fig. 10. 



PLATE XXIV. (All the bones figured in this plate are from the Coll. U. S. Nat. Mus. and their 

 numbers are shown upon the specimens. They are all adult, and natural 

 size.) 



Fig. 13. Left lateral view of the skull of Phalacrocorax pelagicus robustus. 



Mandible removed. (See Fig. 18.) 



Fig. 14. Left lateral view of the skull of Phalacrocorax albiventris. Man- 

 dible removed. (See Fig. 21.) 

 Fig. 15. Left lateral view of tfie skull of Phalacrocorax urile. Mandible 



removed. (Specimen bears no number.) 



Fig. 16. Basal view of the skull of Phalacrocorax melanoleucus. Mandi- 

 ble removed (Australia). There is but one known species of cormorant in 

 the world smaller than this one. 

 Fig. 17. Left lateral view of the skull and mandible of Phalacrocorax 



dilophus. Mandible detached. (See Fig. 19.) 



Fig. 18. Superior aspect of the skull of Phalacrocorax p. robustus. Mandi- 

 ble removed. (See Fig. 18.) 



Fig. 19. Superior aspect of the skull of Phalacrocorax dilophus. Mandi- 

 ble removed. (See Fig. 17.) 

 Fig. 20. Superior aspect of the skull of Phalacrocorax melanoleucus. 



Mandible removed. (See Fig. 16.) 



Fig. 21. Superior aspect of the skull of Phalacrocorax albiventris. Man- 

 dible removed. (See Fig. 14.) 



This series of specimens is designed to show the marked variation in form 

 of the skull among the cormorants (Phalacrocoracidce), ranging all the 

 way from the much vertically compressed skull of P.p. robustus (Fig. 13) 

 to the lofty skull of P. albiventris (Fig. 14). 



PLATE XXV. Fig. 22. Dorsal view of the trunk skeleton of Phalacrocorax urile. with chain 

 of cervical vertebrae naturally articulated but curved far backward and to the 

 right. Reduced one half. The skull shown in Fig. 15 belonged to this skeleton. 

 Fig. 23. Left lateral view of the trunk skeleton of Phalacrocorax urile. Re- 

 duced one half, and the same specimen as shown in Fig. 22. 



