COAT CHARACTERS IN GUINEA-PIGS AND RABBITS. 



49 



pigmented animals (at least in a state capable of becoming active as a 

 result of matings with albinos). 



Let us now inquire whether Darbishire's experiments indicate the 

 existence of these various hypothetical classes or not. Darbishire gives 

 in the first part of his Table E, page 35, the results of mating inter se 

 dark-eyed pigmented animals of generation F 2 .* On the "ancestry" 

 hypothesis these should all breed much alike, for their ancestry is sim- 

 ilar in all cases ; on the hypothesis which I have stated, they include 

 the four distinct sorts of individuals which I have called classes (i) to 

 (4), page 48, and these will breed very differently one from another. 

 An examination of Darbishire's table shows that in fact the various 

 pairs of pigmented dark-eyed animals gave results of four different sorts. 



I. The following pairs gave young of three sorts dark-eyed, pink- 

 eyed, and albino : 



On the Mendelian hypothesis each of the parents in these three fami- 

 lies must have furnished gametes bearing the pink-eyed character as 

 well as gametes bearing the albino character. If so, and if each of these 

 characters was represented in half the gametes formed, and the two 

 characters were independent of each other, then the parents were of 

 class ( i) , page 48, and the young should be as 9 P d to 3 P p to 4 A, 

 which approximates roughly the observed 7 to 4 to 4. 



II. The following pairs gave only dark-eyed and pink-eyed young, 

 without albinos : 



* I adopt here and in the following pages Bateson's convenient notation for 

 the successive " filial " generations following a cross, viz, F t , F 8 , F 8 ,etc. 



