292 MR. H. SAUNDERS ON THE GREY-CAPPED GULLS. [May 5, 



Grey-capped Gulls for which Bonaparte formed the subgenus Cir- 

 rhocephalus (Naumannia, 1854, Heft iv. p. 213). 



There are two closely allied species, which during the breeding- 

 season, and, as I believe, throughout a considerable portion of the 

 year, bear a hood of a pale French grey, slightly darker at the 

 margins, round the nape and throat, viz. : — 



Larus phjeocephalus, Sw. B. W. Afr. ii. p. 245, pi. 29 

 (originally written L. poiocephalus), a native of West Africa and the 

 interior up to Lake Ngami ; and 



Larus cirrhocephalus, Vieillot, N. D. xxi. p. 500 ; Gal. Ois. 

 ii. p. 223, pi. 289 ; the Gaviota cenicienta of Azara, found in Brazil 

 and the States of La Plata. 



In their general appearance these Gulls closely resemble each 

 other ; and both Blasius and Schlegel have considered them to be 

 identical— an opinion the value of which is somewhat impaired by 

 the fact of their having confounded one or both of these species 

 with others from which they are most certainly distinct. This has 

 doubtless arisen from the want of a sufficient series in which the 

 localities have been duly recorded ; for specimens of the birds in 

 question, and of those with which they have been confounded, are 

 extremely rare in collections ; and it is only recently that I have 

 been able to obtain such a series as would justify my speaking with 

 some confidence on the subject. 



First, as regards the distinctness of the African and the American 

 forms, I have before me the following specimens : — 



Larus ph^eocephalus. 



Senegambia, Swainson's coll., Cambridge Mus. Believed to be 

 the type : ad. 



Walvisch Bay (Andersson), probably in October. Ad. ; full hood. 



Lake Ngami {Chapman, May 18G3). Hood slightly imperfect. 



Wing 12-5, tar. 1*8-2, middle toe and nail 17, bill 1*4. Colour 

 of legs and bill orange-red. 



Larus cirrhocephalus. 



Buenos Ayres, S & $ ad., several specimens, those killed in April 

 and November having the grey cap equally defined ; also immature 

 specimens obtained in April, and in which the grey hood is appearing, 

 although the dark bar to the tail and the brown feathers on the 

 shoulders still remain. 



2 . Chorillos, near Lima, lat. 12° 10' S.; the first recorded instance 

 of its occurrence on the Pacific coast. This was shot by a friend 

 resident at Lima, whom I had asked to collect Gulls &c. 



Wing 13-13-5, tar. 2-2-2-4, middle toe and nail 2, bill 6*1. 

 Bill legs, and feet lake-red ; in a very old male of the brightest 

 crimson. 



The same description would apply to either : the hood pale grey 

 with a dark margin ; the wings and mantle rather darker than the 



