in. 



INHERITANCE IN GUINEA-PIGS. 

 Tabu 60— Continued 





18 

 66 

 67 



( !n>88. 



53 

 69 



Cross. 



55 



S.-i 



38 



\ Iri E Tri 



Bm l-toe E Tri 



A l toe, tri Sra pure lea. 



\ Sm pure rut 



Total 



Expectation Sa. 



Ss XSS 



C, D Tri E Tri 



C, D Tri Sm pure rut . 



Total 



B 



Espeetation Ss + SS. 



SS X SS 



E Tri E Tri 



Expectation SS 



B 



2 



13 



5 



3 



23 



D 



30 



D 



11 



E 



15 



11 



B 



D 



E 



The interpretation given is no doubt open to objections. In some 

 cases the ratios seem rather aberrant. This is in part due to the small 

 numbers, but also to the overlapping of class ranges. In most cases 

 rough B must be considered as full-rough genetically (Rss), but in some 

 cases it is probably partial-rough (RSs). Rough E usually seems to be 

 RSS, but in some cases must be heterozygous (RSs). It has not been 

 demonstrated that factor S of the wild species is identical with the 

 similar factor of the tricolor stock. If not identical, however, the 

 latter stock differs from the wild by two mutations which neutralize 

 each other, while if identical we can consider that the original tricolor 

 stock had simply persisted in the primitive condition, never having 

 had the rough intensifying mutation, s, of the fancier's roughs. 



MINOR VARIATIONS. 



Probably part of the minor variations in roughness are due to chance 

 irregularities in development which are not hereditary. This is indi- 

 cated by the Blight asymmetry not uncommonly present. This asym- 

 metry seldom amounts to more than the absence of a member of one 

 pair of rose! tee. 



No Mendehan analysis has yet been attempted for minor variations, 

 but certain hereditary differences between different stocks are quite 



