326 Count T. Salvadori — Notes 



last year (1904) Kleinschmidt * proposed to regard Corvus 

 corax varius of the Faroe Islands as a mutation. As it, 

 however, displays partial albinism in a variable degree in 

 different specimens, I do not think that it can be regarded 

 as a typical example of mutation. Sylvia heinekeni of 

 Madeira, brought forward on the same occasion by the 

 same author as another instance of mutation among birds, 

 is by others regarded as " an instance of partial melanism " f, 

 or "una varieta melaniea" %. 



If the case of Tetrao urog alius lugens were to be ranked as 

 a mutation in an atavistic direction, it might perhaps be 

 regarded as a mutation in a progressive direction that the 

 young of Cygnus olor in down, and again in their first 

 plumage and then permanently, are white §, and thus give 

 rise to the form C. immutabilis. But other authors say that 

 the characteristics of this Swan are not constant and regard 

 it only as " a quasi-albino produced by domestication " ||. 



Chrysolophus obscurus has also been regarded as a 

 mutation, but I pass over this case as we may soon learn its 

 full history. Dr. C. Kerbert, of the Zoological Gardens of 

 Amsterdam, has the material for its investigation. 



XVIII.— Notes on the Parrots. (Part IV.) 

 By T. Salvadori, H.M.B.O.U.H 



Fam. V. PsiTTACiDiE (Cat. Birds Brit. Mus. xx. p. 137). 

 Subfam. Nasiternin^e (op. cit. p. 138). 



This subfamily contains only one genus, Nasiterna, 

 which, according to some authors, ought to be named 

 Micropsitta, a suggestion that I am not prepared to follow, 

 as the latter name was proposed as a subgenus of Psittacus 

 and not as a real genus. 



* According to the " Compte Rendu" of the Congress, p. 212. 



t Cat. B. Brit. Mus. v. p. 25. 



X Giglioli, Manuale di Ornitol. Ital. p. 276. 



§ Cf. F. A. Forel, 'Le Leman,' t. iii. pp. 308-326. 



|| Cat. B. Brit. Mus. xxvii. p. 38. 



51 Continued from p. 131. 



