163. Mr. H. Seebohm on the Ornithology of Siberia. 
and in Kamchatka (Avittlitz, in Mus. Petr. fide Schrenk). 
In spring and autumn on migration it has been found in the 
Caspian Sea (Karélin,in Mus. Petr.) and at Ayan, in the Sea 
of Okotsk (Wosnessensky, in Mus. Petr.). The type of this 
species is a skin from Greenland ; and it is described as not 
uncommon at St. Michael’s, in Alaska; but until we have 
evidence that it breeds on the American continent we can 
scarcely consider it as more than an occasional visitant there. 
LARUS CACHINNANS, Pall. 
Larus affinis is, par excellence, the Arctic Herring-Gull. 
L. cachinnans might with equal propriety be called the Lake 
Herring-Gull. It appears to confine itself during the breed- 
ing-season to lakes, rivers, andinland seas. It is the common 
Herring-Gull of the Mediterranean, the only species known 
at St. Petersburg, and the only species known to breed in the 
Caspian Sea (Radde & Karélin, in Mus. Petr.). It is found in 
the breeding-season near the Aral Sea (Severtzoff, in Mus. 
Petr.), Lake Saissan (Finsch & Brehm), S.E. Mongolia (Pree- 
valsky, in Mus. Petr.), Lake Baical and the island of Olchon, 
in a lake to the south-east (Radde, in Mus. Petr.). This Gull 
has yellow legs when fully adult, with a mantle intermediate in 
shade between that of L. argentatus and L. affinis. Mr. Howard 
Saunders has also pointed out to me the difference in the 
respective lengths of the tarsus and the middle toe, including 
the claw. In L. fuscus and L. affinis the tarsus is longer than 
the foot, whereas in L. cachinnans and L. argentatus the con- 
trary is the case. In L. fuscus and L. affinis it is the excep- 
tion for the second primary to have a subterminal white spot, 
whilst in L. cachinnans and L. argentatus it is the rule. 
In the St.-Petersburg Musenm there are three skins of 
L. occidentalis collected by Wosnessensky on the coast of 
Southern California. This is a large form of L. fuscus, with a 
short thick bill, very dark mantle, no wedge-shaped markings 
on the primaries, and, as far as one can judge from dried skins, 
very yellow legs. There is also a skin obtained by Wosnes- 
sensky at Kodiak, on the North-American coast, which looks 
like a skin of L. argentatus. 
[78] 
