324 MR. H. SAUNDERS ON THE STERCORARIIN^E. [Mar. 21, 



the south of the Equator. The affinities of this well-defined form are 

 decidedly with S. catarrhactes, and not with S. antarcticus ; it is, 

 indeed, a somewhat slighter bird than the former, and remarkable 

 for its rich cinnamon-coloured underparts, wing-coverts and axil- 

 laries. The presence of this species on the shores of the South Pacific 

 may be accounted for by the cool stream of water, about 300 miles 

 wide, and known as Humboldt's current, which runs northwards from 

 the Straits of Magellan, along the coasts of Chili and Peru. This 

 cool band abounds in fish ; and in consequence of these altered con- 

 ditions we find there at least six species of Gull, some of them nu- 

 merically abundant ; whereas on the east coast of America there is a 

 noticeable scarcity of Gulls within the tropics. Where Gulls are 

 found, the stout heavy forms of Skua can pick up a living ; their 

 more lightly formed congeners can rob the Terns, and the two long- 

 tailed species are more than a match in flight for the Arctic Tern ; but 

 against that family the Great Skuas would have little chance ; and 

 hence, probably, their more restricted range. If this species should 

 prove to have its breeding-places in the North Pacific, it is somewhat 

 singular that it should never have been observed north of the Equator, 

 and that the only specimen of a great Skua recorded from the north- 

 west coast, namely at Monterey, California, lat. 44° N., is clearly 

 from the description given, S. catarrhactes. If, on the other hand, 

 it should prove to be a denizen of the southern hemisphere, it is still 

 more remarkable that we should find in such close proximity to S. 

 antarclicus a form whose affinities are with S. catarrhactes. In 

 order of arrangement it should follow the latter species, although in 

 the present case I have taken it last for convenience of treatment. 



Stercorarius fomatorhinus. 



Stercorarius striatus, Brisson, Orn. vi. p. 152, pi. 13. fig. 2 (juv.), 

 17o0. 



Larus keeask (part.), Latham, Ind. Orn. p. 818 (1/90). 



Larus parasiticus, Meyer & Wolf, Tasch. I). Vog. ii. p. 490, 

 descrip. p. 492 (1810), nee auctorum. 



Cotarracta parasita, var. camtschatica, Pallas, Zoogr. Ptosso-As. 

 p. 312(1811). 



Lestris pomarinus, Temm. Man. d'Orn. p. 514 (1815) ; Audubon, 

 B. Am. vii. p. 186, pi. 451 (1844); Ross, in Parry's 4th Voy. App. 

 p. 196 (1828), fide Newton. 



Stercorarius pomarinus, Vieillot, N. Diet. Hist. Nat. xxxii. p. 158 

 (1819) ; De Selys-L. F., Belg. p. 155 (1842); Gray, Gen. of B. iii. 

 p. 653 (1849) ; Coues, Proc. Phil. Ac. 1863, p. 129 ; B. Ross, Nat. 

 Hist. Rev. 1862, p. 2b9 (Gt. Slave Lake, very rare); Wright, Ibis, 

 1864, p. 151 (Malta); Gurney, Audersson's B. of Damara Land, 

 p. 357 (lb/2). 



Cataractes pomarina, Steph. in Shaw's G. Zool. xiii. p. 21 6 (1826). 



Cataractes pomarinus, Selby, 111. Brit. Orn. ii. p. 517 (1832). 



Lestris sphceriuros, Brehm, Vog. Deutsch. p. 718 (1831). 



Lestris striatus, Eyton, C. Brit. Birds, p. 51 (1836). 



Lestris pomarina, Faber, Prod. Island. Orn. p. 104 (1822); Sw. & 

 [8] 



