VOL. VII.] ERYTHRISM IN EGGS. 257 



at one or two localities on the Norwegian coast, especially 

 on the islands off Vardo m East Finmark. Professor 

 Ne^^^;on's collection contained specimens taken as long 

 ago as 1855. They were first ascribed to the Glaucous 

 Gull, and under this name eggs have been referred to by 

 Dixon {Nests and Eggs Non-indigenous Brit. Birds, p. 289), 

 and are figured by Seebohm {History of Brit. Birds, pi. 50), 

 and more accurately in his Coloured Figures of Eggs 

 Brit. Birds, pi. 32. More careful investigations by the 

 late H. J. Pearson and others showed that these eggs in 

 some cases were undoubtedly laid by Herring-Gulls, that 

 the Glaucous Gull did not breed in the district, and that the 

 only other species nesting in the vicinity were L. marinus 

 and L. fuscus. The collections of Messrs. H. J. and C. E. 

 Pearson contain fine series of these eggs, as also does that 

 of Professor Koenig (fifteen) at Bonn. The Cambridge 

 Museum has eleven specimens, and there are several in 

 the British Museum (wrongly catalogued as L. glaucus), 

 while Mr. Massey has a wonderful series of thirty-three 

 red eggs, some of which are apparently L. marinus. Among 

 other collections in which the red type is represented are 

 the Tromso Museum, the Swedish National Museum (Ottosson 

 collection), the Gothenburg Museum, and the collections of 

 Messrs. R. H. Read (three), P. C. Musters, W. Rothschild, 

 F. C. R. Jourdain (three), N. F. Ticehurst (one), and P. F. 

 Bunyard (three). 



Great Black-backed Gull {L. marinus). — This species 

 appears occasionally to produce erythristic eggs in northern 

 Norway. Besides those in Mr. Massey's collection already 

 mentioned, the late Dr. Ottosson had examples now in 

 the Stockholm Museum. 



Iceland Gull {L. leucopterus). — ^The Tring Museum 

 contams two dark red eggs from Labrador ascribed to this 

 species. 



Razorbill {Alca torda). — Though the extent of variation 

 is not so great as in the Guillemot, and the majority of eggs 

 are marked with various shades of brown on a light ground, 

 some eggs of this species can with reason be classed as 

 erythristic. 



Common Guillemot {Uria t. troille). — ^The range of 

 variation is so well-known in this species, that it is 

 unnecessary to go into detail beyond stating that ^3oth 

 extremes of cyanism and erythrism are to be met with. 

 In the latter types the ground-colour ranges from white 

 to buff and pinkish-brown, and the markings from light 



