118 



GENETICS 



SPR 



SpR 



sPR 



SPr 



spR 



Spr 



sPr 



spr 



FIG. 22. The eight phenotypically different kinds of guinea-pigs 

 in the F a generation of a trihybrid. S = short hair ; s = long 

 hair or angora ; P = pigmented coat ; p = non-pigmented coat 

 or albino ; R = rough or resetted coat ; r = smooth coat. 

 Drawn from Castle's photographs by C. J. Fish. 



