82 MB. W. p. PTCRAJT ON THE [Feb. 15, 



The following papers were read : — 



1. Contributions to the Osteology of Birds. 

 Part I. Steganopodes. By W. P. Pycraft. 



[Received February 12, 1898.] 



(Plates VII. & VUI.) 



It has recently fallen to my good fortune to be set the task of 

 determining and arranging the large collection of birds' skeletons 

 at the British Museum. I propose to embody the results of my 

 work in a series of papers of which this is" the first. Before 

 going further, I would like to remind those interested that I 

 shall be most grateful to receive, on behalf of the Collection, 

 embryos, nestlings, and adults of all Orders, for there are many 

 gaps left by imperfect specimens, and otherwise, which much need 

 to be filled up. 



The Pelicans, Tropic-birds, Frigate-birds, Cormorants, Darters, 

 and Gannets all agree in one point — all four toes are united in a 

 common web. This fact has been deemed by some of sufficient 

 importance to justify their separation from the rest of the 

 Carinatte, to form a special group by themselves — the Steganopodes. 

 Others, on account of anatomical differences which obtain amongst 

 certain of the groups thus brigaded together, are inclined to doubt 

 whether this separation is a vaUd one, whether the value of this 

 single external character is sufficiently great to be regarded as a 

 primary dividing factor. The stumbling-blocks which threaten 

 the general harmony are Pliaethon and Fregata. 



I hope, in the present paper, to show that, after all, the " toti- 

 palmate " foot may be adopted as the shorthand sign of the gi-oup : 

 to show that (1) all are closely related ; that (2) they cannot be 

 broken up to form one or more suborders or subdivisions of equal 

 value, but that (3) they must be regarded as a whole, as a suborder 

 or subdivision of some larger group ; and that (4) they cannot 

 consistently be merged as a whole with that larger group. 



The most important witness to the integrity of the Suborder is 

 the skull. Three types can be easily distinguished : — 



1. Basitemporal plate shield-shaped, with a free edge 



anteriorly forming a floor to the Eustachian tubes, or 

 rather grooves. 



2. Basitemporal plate triangular, its lateral borders fused with 



the basisphenoid, free anteriorly and contributing to 

 form the mouth of the Eustachian aperture. 



3. 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 running across the basisphenoid. 



The first of these is the most primitive, and agrees precisely with 



