NATURAL SCIENCES OF PHILADELPHIA. 301 



nearly with the measurements.* I think, then, that there can he no reason- 

 ahle douht of the propriety of referring the large northern specimens to the 

 argentatoides of Richardson and Bonaparte. These same specimens were, 

 immediately upon their reception, referred unhesitatingly to Californicus of 

 Lawrence, by both Prof. Baird and myself. We have critically examined 

 them, and find it impossible to distinguish them from undoubted specimens 

 of Californicus. 



The size is somewhat greater ; but not more so than would be expected 

 from the much more northern habitat of the specimens examined ; and, more- 

 over, the numerous specimens differ among themselves to a remarkable de- 

 gree, the smallest of the northern ones not exceeding the largest of the 

 southern. Thus, though a large northern bird and a small southern differ so 

 much that it would seem quite reasonable to separate them, there are found 

 intermediates of every grade of dimensions. The upper parts of the northern 

 bird are, perhaps, a shade lighter than are California specimens ; but other- 

 wise, we cannot appreciate the slightest distinctive characters. Now, it is not 

 improbable that there should be in America two species of white-tipped pri- 

 niaried Gulls, the one from Arctic (and Eastern ?t) America and the other 

 from the Pacific, differing from each other, on an average, in size ; hut in the 

 absence of tangible characters, I do not venture to separate the two. I there- 

 fore, at present, quote " Larus argentatoides, Bp. et Rich, nee Brehm" as 

 synonymous with " Californicus, Lawr.," leaving it to future investigation to 

 settle the point definitely. 



The only discrepancy to be reconciled in the description of Richardson, is 

 the statement "legs flesh-colored " The legs of Californicus are of a dusky 

 olivaceous greenish or yellowish, their interdigital membranes bright chrome 

 yellow, with a slight tinge of green. In this respect, as well as in a general 

 less powerful and robust organization, weaker bill, &c, it shows an evident ap- 

 proach to the "Mew Gulls" (Delawarensis, canus, &c), and apparently forms 

 the connecting-link between the powerful Herring- Gulls, with their robust 

 bills and flesh-colored legs, and the group of which canus is the type. J But 

 Mr. Lawrence himself, in his description given in the General Report, says 

 also "legs flesh-colored," though the color is given correctly in the Ann. N. 

 Y. Lye. N. H. The descriptions of both these authors were most probably 

 drawn up from the dried skins, in which, as attested by a large series before 

 me, the legs appear of a dingy undefinable color, which might readily be sup- 

 posed to be the change produced in drying of the flesh color. My authority 

 for the statement as to the color of the legs, is the labels attached to the 

 specimens, containing the color of bills, eyes, legs, &c, taken from the recent 

 bird before skinning. 



The type of Californicus has been kindly furnished by Mr. Lawrence for 

 examination. It is moulting, and some of the primaries are not fully grown 

 out. The white apical space on the first primary is interrupted by a narrow 

 transverse bar of black. Another specimen before me is in precisely the 

 same condition. In other skins of the series the black bar is resolved into 



not take into special consideration the character of the extent of the bluish white bases 

 t>f the quills; and since the black nearly occupies the whole of the outer web of the 

 first, he would not have particularly noticed the extent to which the bluish white runs 

 up on the inner vane. 



* I am inclined to think that Richardson drew up his measurements and descriptions 

 from the largest as well as the most perfect specimens, since, in several instances, the 

 measurements seem above the average, though not exceeding the dimensions of large 

 individuals. 



t Bonaparte (Syn., 1828, 360) says his argentatoides is " common near New York and 

 Philadelphia." 



t This fact is also an argument for the impropriety of separating the two groups gene 

 rically, as has been done by some authors. 



1862.] 



