182 MR H. SAUNDERS ON THE LARIN.E. [Feb. 5, 



Gabianus bathyrhynehus, Bruch, J. f. Orn. 1855, p. 280; Bp. 

 Consp. Av. ii. p. 212 (1857). 



Gabianus georgii (King), Bp. Consp. Av. ii. p. 213 (1857). 



Hab. South-west portions of Australia, Bass's Straits, and Tas- 

 mania ; not included by Mr. Buller in his ' Birds of New Zealand,' 

 but there are three specimens labelled from that locality in the British 

 Museum, obtained by the Antarctic Expedition. 



Mr. Gould's plate hardly gives a correct idea of the dimensions and 

 great depth of bill in this fine species, which may easily be distin- 

 guished by this feature in all stages. In the adult the tail is 

 crossed by a black band ; and this peculiarity in the plumage, coupled 

 with the stout bill, seems to place this species midway between the 

 typical Gulls and those of the next group. The value of Gabianus 

 as a genus for this species has been already discussed. 



20. Larus belcheri, Vigors. 



Larus belcheri, Vigors, Zool. Journ. iv. p. 358 (1829); id. Zool. 

 Beecher's Voy. "Blossom," p. 39; Schlegel, M. P.-Bas, Lari, p. 9 

 (1863), excl. syns.; Scl. & Salv. P. Z. S. 1871, p. 575. 



Adelarus belcheri, Bruch, J. f. Orn. 1853, p. 107; id. 1855, 

 p. 279 ; Bp. Naum. p. 212 (1854). 



Leucophceus belcheri, Bp. Consp. Av. ii. p. 232 (1857). 



" Larus fuliginosus, Gould," Cassin, U.S. Expl. Exp. Orn. p. 378 

 (1858), nee Gould (Cape Horn to Callao). 



Larus frobeenii, Phil. & Land. Wiegm. Archiv, 1861, p. 292. 



Icarus frobeni, iid. Cat. Aves Chil. An. Univ. Chil. torn. xxxi. 

 p. 288. 



Hab. West coast of S. America, from Callao southwards to Chili, 

 the western portions of the Straits of Magellan, and down to Cape 

 Horn. 



I have the fully adult bird with pure white head and underparts 

 from Chorillos, near Callao, Peru ; but I observed the immature birds 

 with dark hoods in far greater numbers. Although several of these 

 Pacific Gulls have a hood in the immature stage, which is lost in the 

 adult, in none of them is the change so remarkable as in this species. 

 I confess that I cannot see any adequate reason for giving it generic 

 rank ; but Bonaparte thought differently, for he made it the type of 

 his genus Procellarus, being quite unaware that it was absolutely 

 the same species as the bird which he had already located in the 

 genera Leucophceus and Adelarus ! 



Dr. Coues, in a general notice of American Gulls, under the head 

 of L. heermanni (B. of N.W. p. 642), says that L. belcheri is "not 

 a white-headed Gull at all," though he afterwards says that he 

 should not be surprised if, in the adult state, it lost its hood. In 

 this last surmise he is quite right ; the adult L. belcheri is a perfectly 

 white-headed Gull, at the first glance being like a stout L.fuscm 

 with a black band on its tail. 



21. Larus heermanni, Cassin. 



Larus heermanni, Cassin, Proc. Ac. Nat. Sc. Philad. vi p 187 

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