1887.1 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 381 



thin crest of booe foi^ a considerable distance, wliile in Daptlon these 

 depressions do not meet here by several millimeters. Moreover, we 

 notice behind in one skull of PelecanoMes that the crotaphyte fossae are 

 very deeply depressed, and are bounded posteriorly by a thin, raised, 

 almost knife-edged crest of bone; no such feature marks the skull of 

 Daption. Viewed from beneath, we find the basipterygoidal processes 

 developed in one specimen, while the heads of the i>tery golds themselves, 

 opposite these projections, are much expanded in the horizontal i)lane 

 being compressed in these parts from above downwards. The "postero- 

 external angles" of the palatines are rounded off, and tbe hinder moieties 

 of these bones are in contact for a considerable distance beneath the 

 rostrum of the sphenoid. Anteriorly, the palatines are carried directly 

 forwards, and these extremities do not curve outwards, as I described 

 them above for Daption. The vomer of this specimen is proiortionately 

 narrower than the corresponding bone is found to be among the Ful- 

 mars, though it possesses much the same shape. 



In the condition of its iuterorbital septum ; the form of its lacrymai 

 bone; the position and proportions of its j^ftrs^^Zawa; and the style of its 

 quadrate, this skull of Felecano'ides almost exactly agrees, except in 

 l)oint of size, with the corresponding features in the skull of Daption. 

 It also possesses the same peculiar pattern of a post-frontal process, 

 which forms a prominent wing-like projection, standing out from the 

 side of tbe skull, a character well drawn for us by Forbes iu liis figure 

 of the skull of Q^stralata Icssoni, alluded to above. 



As tbe sternum and shoulder girdle of this bird agree so closely with 

 both tbe description and figures given by Forbes for P. iirinatrix, it will 

 obviate the necessity of my saying anything further about them here. 



The sl-uJl, sternum* and sJioulder girdle* of Gepphus eolumba.~The. 

 skull of this species was not in my possession at tbe time I completed 

 my memoir on the arctic water birds, but a figure of its superior aspect 

 has been given ns by Sir Richard Owen in his memoir upon the osteol- 

 ogy of the Great Auk, and the form is so well known generally that I 

 can dismiss it in a few words. There is a great deal about it to remind 

 ns of the skull as we find it among the Laridce, and, indeed, in many 

 particulars it comes nearer the skull of a true Larus, as, for instance L. 

 calif ornieus, than does such a form as Larus Philadelphia. Its mandibles, 

 however, are gradually tapered out to a point, whereas iu the Gulls 

 as we know, the superior mandible is gently decurved at the tip. The 

 characters presented us upon the under side of the skull in this Guil- 

 lemot are almost exactly, practically exactly, as we find them iu the 

 typical Gulls, The relations of these groups I have elsewhere attempted 

 to define, in so far as their osteology seems to indicate them. 



The sl-ull* sternum* and shoulder girdle* of Larus argentatus.—l 

 find no special differences among these bones and tbe corresponding 

 specimens belonging to the National Museum, which I have already 



