132 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



ivnd Kerguelen Island, I do not detect any constant characters that 

 may seem to serve to distinguish birds from these localities. The 

 gonydeal angle in two specimens from Kerguelen Island is very 

 prominent but is approached in this respect by birds from South 

 America. Two specimens from New Zealand seem to have the wings 

 and mantle somewhat blacker than others, but here again the differ- 

 ence may break down when recourse is had to a fair series from else- 

 where. The bird from South Shetland I have not examined. On 

 the whole, specimens from the scattered localities at hand seem re- 

 markably constant in their conformity to one type of coloration. 



The similarity in color and structure between L. doniinicanus and 

 L. marinus from North Atlantic and Arctic regions is striking, and 

 in final analysis birds from the two regions seem separable by dif- 

 ference in size alone so that one may well question the degree of re- 

 lationship between the two. In habit and distribution the two are 

 complementary one to the other, and it seems logical to conclude 

 that they have arisen from one parent stock. Differentiation in the 

 two regions has apparently progressed to a point where we may 

 recognize the two as full species though the propriety of calling 

 them subspecies of one form may be considered. 



Three specimens were taken near Lavalle, Buenos Aiies, a male 

 on October 25 and a male and a female on November 3. All are 

 in partial immature dress. The male first mentioned above has 

 molted in part into adult plumage though worn brown feathers 

 are scattered over the dorsal surface, the primaries are still old, 

 and only part of the tail has been renewed. The neck and lower 

 surface are still more or less mottled. The two secured on Novem- 

 ber 3 are less advanced in stage of plumage though dark feathers 

 are appearing on the mantle. The female is small, so that when 

 I killed it I was under the impression that it w^as an individual of 

 some other species. 



In June the Dominican gull, known as gaviota cocinera^ was com- 

 mon in the harbors of Rio de Janeiro (June 16), Montevideo, and 

 Buenos Aires. At Berazategui, Buenos Aires, a number were re- 

 corded along the Rio de la Plata in company with smaller gulls on 

 June 29. In the vicinity of the coast near Lavalle, Buenos Aires, 

 the species was common from October 25 to November 13. The 

 birds ranged along the tidal mouth of the Rio Ajo and in the Bay 

 of Samborombon, or occasionally came a few leagues inland in search 

 of refuse about the killing pens at the estancias. On the beach 

 south of Cape San Antonio they were fairly common. The ma- 

 jority seen at this season were in immature dress and those taken 

 were not in breeding condition. 



On December 13 I saw a number in the bay at Bahia Blanca, 

 where they gathered Avith harsh calls to feed on refuse cast over- 



