90 Experimental Zoology 
the eyes the color, C, always dominates; but the color of the 
hair is yellow, because yellow dominates over black. 
The four types with which Cuénot has experimented give 
eighteen different combinations, which he shows by means of 
the following table: — 
HOMOZYGOTES HETEROZYGOTES 
COLOR 
OR PURE RACES MoNnoHYBRIDS DIHyYBRIDS 
CGCB CGAB 
Gray CG (wild) CGAG 
Black CB CBAB 
Yellow cY CYCG CYAG 
* CYCB CYAB 
CYAY 
Albinos AG ‘ AGAB 
AB AGAY 
AY ABAY 
Of these eighteen types there are six that are pure races,’ 2.e. 
they produce germ-cells that are all alike (homozygotes). In- 
bred, they give always the original types in all successive gen- 
erations, and this holds also for the three albino types, having 
the latent characters gray, black, and yellow, AG, AB, and AY. 
The other twelve types are heterozygotes, resulting from the 
crossing of pure races. Of these, nine are monohybrids, hav- 
ing only one pair of antagonistic determinants; and three are 
dihybrids, having two pairs of antagonistic determinants. 
It will be seen that Cuénot thinks that albinos are not nec- 
essarily all alike, although they may breed true to the albino 
type, but that they are different according to the latent char- 
acter that each contains. The latent character may appear in 
1 According to Cuénot’s nomenclature. The three albinos, homozygotes, be- 
long in my opinion to a different category, for although they breed true, yet they 
contain a latent color that may come out in crossing. 
