No. 579] ALBINO SERIES OF ALLELOMORPHS 141 



dilute variety in the second generation at latest. The 

 writer has done this for all of the types mentioned by 

 starting with the cream variety. 



The third condition is not so familiar as the others. It 

 has appeared at the Bussey Institution only in the de- 

 scendants of three guinea-pigs brought from Peru by Pro- 

 fessor Castle in 1911. Among these black is reduced to 

 sepia (or ' ' blue"), indistinguishable from the "blue" of 

 the dilutes. Eed is reduced to white. Not a trace of yel- 

 low pigment has been found in guinea-pigs with this al- 

 lelomorph. One of the most striking features of this 

 condition is the glowing red color of the eyes, easily dis- 

 tinguishable from the black eyes of the intense and dilute 

 guinea-pigs as well as from the pink eyes of the albinos. 

 There is a deficiency of pigment in both retina and iris. 

 Because of this feature this condition will be known as 

 red-eye. It was announced as an allelomorph of albinism 

 by Castle (1914) . Permission has very kindly been given 

 the writer to present in this paper data on the red-eye 

 condition, in the work on which he has been associated. 

 With the red-eye factor, the blacks, reds, golden agoutis 

 and black-and-red tortoise-shells become red-eyed blues, 

 red-eyed whites, red-eyed silver agoutis and red-eyed blue- 

 and-white tortoise-shells, respectively. These four varie- 

 ties have all been obtained by crossing one of them, the 

 red-eyed silver agouti, with various stock guinea-pigs 

 and extracting the different combinations in F 2 . The 

 red-eyed white is an interesting variety thus derived. 

 Red-eyed whites have been tested by crosses with reds and 

 creams and have been shown conclusively to be the red- 

 eyed representative of these varieties, such crosses having 

 given 9 reds, 3 creams, 6 red-eyed whites and 6 albinos 

 only. This red-eyed white demonstrates most forcibly 

 the complete inhibition of yellow in the presence of the 

 red-eye factor. 



In the albino condition black disappears from the coat 

 except in patches on the nose, ears and feet, and occa- 

 sionally some sootiness on the back. In this connection 

 it is interesting to note that nose, ears and feet are gener- 



