272 OSTEOLOGY OF TUBINARES AND STEGANOPODES. 



ward the Pelicans and Cormorants, when we come to compare the skulls 

 of the various forms referred to by that writer this statement will be 

 seen to bave a large measure of truth in it. The points he calls atten- 

 tion to arc very well shown in the figures he presents us in his well- 

 known paper of Procellaria gigantea and Diomedea exulans (P. Z. S., 

 L867, p. 431, Figs. 12 and 13). 



In this particular instance I believe that this opinion of Professor 

 Huxley will some day be verified, or just so soon as we become better 

 acquainted with the entire structure of a number of the forms now sup. 

 posed to be related. Anatomists have amply demonstrated during the 

 past lew years that this single character — the condition of the bones at 

 the roof of the mouth — can not invariably be relied upon, and we must 

 always look into and compare other structures if we wish to correctly 

 judge of the true affinities of birds. The teachings of the law of evolu- 

 tion call for this above everything else that I know of, as we there learn 

 how one such character may be retained while many others in the same 

 organization may go on varying for ages. 



In the skull of the Albatross we see the Pelican in its posterior view ; 

 we see the Petrel; we see the Cormorant and Gannet foreshadowed in 

 its palatines; we see the Fulmar, and we catch glimpses of the Gull; 

 yet how hard it would be to put your finger upou the predominant type. 



Upon lateral view T we have the powerful superior mandible, with its 

 terminal, decurved, and massive book. Its culmen is roundly convex 

 and its dentary borders are cnltrate, the dentary processes behind being 

 thrown down from beneath these lateral edges to meet the palatines 

 below them and to their inner sides. Each nasal has been thoroughly 

 absorbed in the adult, robbed of its individuality, and made to fulfill its 

 part in the creation of this form of skull. 



No nasal septum is present, and the bony nostrils are comparatively 

 small and quite elliptical in outline. From the anterior arc of each, 

 ujion the lateral aspect of this upper mandible, either side, a shallow, 

 longitudinal groove is carried forward, to merge into the dentary edge 

 at the commencement of the mandibular hook. A lacrymal is a highly 

 pneumatic, freely articulated, bone, its descending process meeting the 

 straight maxillo-jngal bar, and its posteroexternal process above being 

 rounded. Its inner border articulates with both the frontal and nasal, 

 here indislinguishably merged together. 



An ethmoidal wing is not very powerfully developed and does not 

 meet the lacrymal, as it does so extensively in the Fulmars and 

 Petrels. 



All the walls of the upper half of the orbit conspire to render it a 

 hemiglobular cavity, the bottom of which is pierced by a considerable 

 foramen leading to the opposite orbit. 



The tract of the olfactory nerve is nearly, quite iu some specimens, 

 bridged over by the extension of the concave anterior wall of the brain- 

 case. The optic foramen is small, circular, and usually distinct. 



