NATURAL SCIENCES OF PHILADELPHIA. 299 



iag the claims of these markings to be considered as of value. The radical 

 difference still exists. 



But if then the terminal marking of the primaries of californicus are like 

 those of the European argentatus, and the two species are nearly identical in 

 size and general robustness, what are the differences between these two 

 species ? Briefly as follows : The European argentatus, though less robust 

 than the apicalis, does not exhibit that decided approach to the " new gull " 

 type indicated in the californicus by its greenish legs. Though the terminal 

 markings of the primaries are quite identical, the character of the bluish bases 

 differ decidedly. In californicus this color is very light, so much so as to be 

 almost white. It runs up further on the primaries (especially on the first), 

 and with a different pattern, its edge being nearly parallel with the shaft for 

 the greater part of its length, and then turning off suddenly at an angle to the 

 edge. It runs up nearly as far on the edge of the feather as in the middle. 

 Now in the European argentatus (and also in Smithsonianus,) this color is but 

 little lighter than the mantle ; runs an oblique course to the edge of the 

 feather ; and goes further up centrally than at the edge of the inner vane, 

 where the terminal blackish descends for a little distance as a narrow margin. 

 Moreover, in californicus the line of demarcation of the two colors is very 

 distinct and decided, while in argentatus, they are more blended at their 

 union. In discussing this point, the habitat of the californicus should not be 

 lost sight of. 



With regard to the name by which this species is to be designated : 



So far as I have been able to ascertain, the species has never been desig- 

 nated by any other name than that of L. argentatus by American authors, it 

 having been always considered by them as identical with the European 

 species of Briinnich. 



The Laroides americanus, Brehm, might perhaps be considered to refer to 

 this species. It is, however, evidently quite a different bird. The brief 

 diagnosis of Brehm is as follows : " Unterscheidet sich von Laroides argenta- 

 toides Brehm durch den etwas kleinern Schnabel und der noch weiter hirsten 

 erhuhten scheitel. " Now the Laroides argentatoides of Brehm is said by that 

 author, "vor alien vorhergehenden " L. major, argentatus and argenteus 

 "an ihrem kleinen Schnabel und iiusserst hohen scheitel zu erkennen." 

 Thus, the L. americanus of Brehm is a bird with a much smaller bill even 

 than L. argentatoides of that author, and therefore cannot possibly be the 

 species now under consideration, which has a larger bill than argentatus, 

 Briinnich. I regard it as not at all impossible that Brehm should have based 

 his species {americanus) on a small specimen of L. californicus, but his diag- 

 nosis is so brief and unsatisfactory that I do not see how the identity of the 

 two names is to be proved positively. 



The Laroides argentatoides, Brehm, is given by Bonaparte and some other 

 authors as the " Larus argentatus ex America," which would make it the bird 

 now under consideration. Brehm's description, however, gives no tangible 

 points of difference, and the measurements indicate a bird rather smaller in- 

 stead of larger than the argentatus, Briinn. The distinctive characters from 

 argentatus are summed up as lying in the smaller size, smaller bill and higher 

 forehead ; features quite at variance with those presented by the species now 

 under consideration. Moreover, the expression " sie ist nordlichate unter 

 alien silbermoven," proves decisively the non-identity of the two. I have 

 been unable to find any other name which could by any possibility be referred 

 to this species. 



There is, in the collection of the United States Exploring Expedition, (Vin- 

 cennes and Peacock,) a Gull labelled as having been obtained in Oregon. The 

 specimen presents the characters of the present species typically, agreeing 

 perfectly with eastern skins. This locality I was at first disposed to consider 

 as erroneous, but very recently specimens received from J. Hepburn, Esq., of 



1862.] 



