358 Eye-Colour in Gaimnarusi 



A Ihino X A Ihino (both may carry Red and Black or only one of tJiein). 



Both spotted. 



Unspotted Spotted 

 Albino Albino 



Family C. 17 h. Expt. 143 97 



Theory 9:7 



Gives 135 105 



Albino X Albino (may carry both Bed and Black). One unspotted, 



one spotted. 



Family A. 4 />. Expt. 143 98 



Theory 9 : 7 



Gives 135 105 



4. Attempts to establish Pure Stocks. 



In consequence of the results just recorded attempts were made to 

 establish by breeding, pure strains (A) of normal unspotted animals 

 and (B) of spotted animals, and to this end two sets of experiments 

 were started. Success did not attend our efforts, no pure strains being 

 obtained, but as the experiments show several points of interest the 

 details are summarised below. 



A. Experiments to establish an Unspotted strain. 



A Hybrid Black stock was selected (i.e. Black carrying Red) which 

 had never been crossed with Albino, and had given very few spots, and 

 out of this a number of unspotted pairs were taken. 



When comparing the relative proportions of spotted animals already 

 given under the heading " selected cases " with those derived from the 

 experiments now to be recorded, it must be remembered that the former 

 are from animals belonging to a very spotted stock carrying Albino, 

 whilst the latter are from a stock which throws very few spotted and 

 carries no Albino. 



The unspotted pairs. 16 pairs of normal-eyed unspotted animals 

 were mated. The detailed records of all the experiments are kept in 

 the laboratory at Plymouth for reference, and only the figures of the 

 largest families are given here. 



(a) Pure Red male x Pure Black female ; 1 pair. 



(b) Hybrid Black male x Hybrid Black female ; 3 pairs. 



One family gave 329 unspotted, and 19 spotted coloured young ; a percentage 



of 5 "4 spotted. 

 Another family gave 346 unspotted and 22 spotted ; a percentage of 6. 

 The third family consisted of 57 unspotted. 



