NATURAL SCIENCES OF PHILADELPHIA. 297 



inches from the tip of the second), and runs further up along the centres of 

 the feathers than on the edge ; on the seventh the black is a mere spot on one 

 or both webs ; the bluish fades into pure white at its juncture with the black 

 on all the feathers except the first. First primary with a subapical spot near 

 the tip, small, rounded, not much more than an inch long, not longer on the 

 outer vane than on the inner, sometimes wanting on the former. Second pri- 

 mary without a white spot, or, if present, it is a mere point. Extreme tips 

 of all the primaries white. Young of the year : Entirely a deep sooty brown, 

 the throat, slightly streaked and the rump transversely barred with whitish, 

 and the feathers of the upper parts edged with grayish or yellowish. Wings 

 and tail entirely black ; bill black. Length 25 inches ; extent 58 ; wing 17'75 ; 

 tarsus 2-50 to 2-60. 



Habitat. Eastern and Western coasts of North America. 



Although it may seem a hazardous undertaking to separate the Herring- 

 gulls of America and Europe, after they have been judged identical by so 

 many authors of repute, I am compelled to do so from a conviction that the 

 differences constantly observable in them are of specific value. Further on it 

 will be attempted to show why they have been confounded. 



The comparison of the extensive series of the North American bird has 

 been made with four perfect specimens of Larus argentatus from Europe, 

 which, I have every reason to believe, represent typically the characters of 

 that species. 



In both birds, the color of the mantle, the color of the bill, the relative pro- 

 portions of the tarsus and toes, the black on the primaries, the small white 

 apical spots, and their bluish bases do not differ appreciably. The tangible 

 differences are the following: 



1st. The whole bird is larger. The difference in the wing in some speci- 

 mens amounts to nearly two inches, and in none is it less than half an inch. 



2d. The bill is larger, longer and more robust. It is especially stouter at 

 the base. The angle is larger, more prominent and bulging ; but at the same 

 time it has not so pointed and well defined an apex. 



3d. The legs and feet are longer and stouter, perhaps even more so than 

 is proportional to the greater size of the bird. The entire difference in the 

 length of the tarsus and middle toe amounts to but little less than half an 

 inch. 



The preceding differences, though marked, I should not consider, iu the 

 absence of other distinctive features, as of specific value. The following dis- 

 crepancies I find it impossible not to regard as conclusive. 



4th. In the European bird, when adult, the first primary has a white ter- 

 minal space just about two inches long. (This is precisely as in cali/ornieus, 

 the similarity being further heightened by the fact that in young birds there 

 is a narrow transverse bar, which gradually resolves itself into two small 

 spots or scollops, and finally disappears.) The second primary has a rounded 

 white spot about three-fourths of an inch in diameter, invading both vanes, 

 but divided into two by the black shaft. In the American bird the first 

 primary has a rounded white spot (of much the same size and character as 

 that on the second primary of the European bird) entirely distinct and sep- 

 arated from the white apex, which is very small. The second primary has no 

 white sub-terminal spot ; or if one is present (which is rarely the case in 

 very old birds) it is exceedingly small. 



. Now it may be urged, that these differences have been noted, but disre- 

 garded as of no value, the nature of the terminal markings on the wings of 

 gulls being considered "notoriously inconstant." There is in the Smith- 

 sonian collection perhaps the most extensive series of American Herring 

 gulls ever brought together. In no single specimen of the series have I ever 

 observed the slightest approach to the large white apical space on the first 

 primary which exists in the European bird ; constantly, so far as I have op- 



1862.] 



