262 Mr. J. H. Gurney^s Notes on 



651. Casarca cana (Gmel.). South-African Shell-duck. 



There can be no doubt that this species is quite distinct from 

 the more northern Casarca rutila, with which Mr. Layard iden- 

 tifies it, as witness Mr. G. R. Gray (Gen. B. App. p. 27), Mr. 

 P. L. Sclater (Proc. Zool. Soc. 1864, p. 190), and Prof. Schlegel 

 (Mus. des Pays-Bas, Anseres, p. 67) . 



657. QUERQUEDULA HOTTENTOTTA, A. Smith. Hottcutot 



Teal. 



This bird inhabits the colony of Natal (Ibis, 1862, p. 154). 



686. Sterna cantiaca, Gmel. Sandwich Tern. 



In European specimens of this Tern there does not appear to 

 be any difference of coloration between the sexes, when in the 

 same state of plumage, unless perhaps that the male in the 

 breeding-season has more of a roseate blush on the breast than 

 the female. The male bird described by Mr. Layard appears to 

 be in the breeding dress, and the female in winter plumage. 



687. Sterna velox, Riipp. Swift Tern. 



688. Sterna galericulata, Licht. Crested Tern. 



Mr. G. B. Gray informs me that he is not satisfied of the 

 identity (as assumed by Mr, Layard) of the Sterna bergi of 

 Lichtenstein with the velox of Riippell, and is disposed rather 

 to identify the former with S. galericulata {S. cristata, Swains.). 



Mr. Layard says that Sterna galericulata "■ may easily be dis- 

 tinguished" from S. velox " by the black of the head being con- 

 tinued down to the bill," whereas the latter " has a broad white 

 forehead." Dr. Hartlaub, on the contrary (Orn. Westafr. p. 

 254) describes S. galericulata as " fronte et vertice albis." This 

 discrepancy leads me to suppose that this species is subject to a 

 seasonal change similar to that to which I have alluded in the 

 case of S. cantiaca. 



Sterna macrura, Naum. Arctic Tern. 



689. Sterna brachypus. Swains. 



Mr. G. R. Gray informs me that the British Museum contains 

 a Tern from the Cape of Good Hope which agrees with Swain- 

 son's description of Sterna brachypus, but that the latter does 



