94 MB. W. P, PYCUAFT ON THE [Teb. 15, 



Key to the Osteolocjy of the Steganopodes,^ 



A. Skull (Plates VII. & VIII.). 



A. Basitemporal plate triangular, its Literal borders fused with the basi- 



spheuoirt, free anteriorly and eontribiitiiig to form the mouth of the 

 Eustachian apertures. 

 a. Upper jaw pointed and with a deep nasal hinge; nostrils pervious; palatines 

 separate, embracing a large vomer ; lachrymal free ; a minute unciform 



(Beddard) '. Fhaetkoii. 



h. Upper jaw very long, depressed, hooked at the tip ; nasal hinge imperfect ; 

 nostrils impervious : palatines fused in the middle line, with a strong 

 median keel ; vomer absent ; lachrymal fused Pclecanvs. 



B. Basitemporal plate shield-shaped, with a free edge anteriorly, forming a 



floor to the Eustachian tubes or groove.-; ; no interorbital septum. 

 a. Aperture of the external nares minute, impervious; palatines meeting in the 

 middle line from the level of the lachrymal backwards, with an ossified 

 supraoccipital style ; lachrymal fused with frontal. 



a'. Upper jaw hooked at the tip; a nasal hinge; laclirymo-nasal fossa large ; 

 temporal lossa narrow and deep ; suprajugular in the form of a 

 splint-like style ; otic process of quadrate lying to the inner side of the 

 squamosal head ; orbito-sphenoid incomplete Phalacrocom.r. 



h'. Upper jaw pointed ; no nasal hinge ; lachrymo-nasal fossa partly 

 enclosed by a large suprajugular ; temporal fossa Tery shallow, 

 lateral walls of optic foramen produced forwards to form a tube ; 

 otic process of quadrate lying behind squamosal head ; orbito-sphenoid 

 complete Plotua. 



C. Basitemporal plate not extending forwards more than half the length of 



the basisphenoid, with which it is so completely fused in the adult as to 

 be traceable only as a thin line or ridge running across the basisphenoid. 



a. Aperture of the external nares almost or quite obliterated ; palatines 



fused in the middle line fi'om the level of the lachrymal backward, with 

 a strong mesial keel; vomer absent: lachrymal fused; postorbita! 

 process emarginate, projecting far outwards beyond the cranium ; orbito- 

 sphenoid complete, with a nasal hinge ; with au interorbital septum. 



'■Sula. 



b. Upper jaw strongly hooked at the tip, and concave dorsally ; nasal hinge 



absent; orbital process of quadrate large, expanded at its free end. 

 Aperture of external nares small, imj)ervious ; palatints not flattened, 

 fused posteriorly, embracing a long, slender vomer ; lachrymal free : 

 with an imperforate interorbital septum Fregata. 



B. VEBTEBB.J;. 

 A. Heteroccelous dorsals. 



a. First dorsal free, remainder fused one with another, and with the 

 synsacrum, but retaining distinct neural spines and transverse processes ; 

 styloid processes of the cervical vertebrse never styliform but fused more 

 or less completely throughout their length either with the pleur- 

 apophyseal lamella, or with a lateral ventral lamella from the centrum. 

 Hypapophyses never more than blunt processes, and occur only on the 

 2nd and 15-18. All the vertebrre are highly pneumatic and pierced 

 by large pneumatic foramina Felecanus. 



^ The " keys " ajjpended are designed for the use of those desirous of deter- 

 mining — at least generically — parts of skeletons which may be either imde- 

 termined or doubtfully named ; they are not meant; to express the systematic 

 relations of the various genera — save that of the skull. " Keys '" to the genera 

 can easily be compiled from these. 



