No. 578] SHORTER ARTICLES AND DISCUSSION 



gray-belly and black." The essential point of his conclusion is 

 that no more than two of these conditions can be transmitted by 

 any one animal. 



The fact that Cuenot in his series of classic papers on color 

 inheritance in mice (1902-1911) recognizes these same four types 

 as forming a group of allelomorphs is not mentioned by M organ, 

 whose paper, without knowledge of Cuenot 's work, might well be 

 taken to contain "the evidence establishing this series of allelo- 

 morphs" as he himself considers that it does. Since Morgan 

 appears to have overlooked Cuenot 's work with these forms, it 

 may be interesting to give a brief statement of Cuenot 's results. 



As early as 1903 Cuenot recognized that albinos, potentially 

 yellows, when crossed with black gave besides yellow offspring 

 either black or agouti young, but not both. This is, of course, 

 evidence that yellow, agouti and black are all allelomorphic to 

 one another. In 1904 he gives formulas (p. 46) showing that he 

 considers this to be the case. At the same time he gives the 

 ratios produced by crossing an albino potentially a heterozygous 

 gray (agouti) with a yellow carrying black, but no agouti, and 

 albinism. For present purposes the albinism in the cross is 

 negligible. Cuenot recognized that the ratio expected from this 

 cross was 2 yellow, 1 black and 1 agouti (gray). He obtained 

 34 yellow, 20 black and 16 agouti; the calculated numbers being 

 38:19:19. Sturtevant (1912) in discussing the allelomorphism 

 or coupling of black, agouti and yellow in mice has also over- 

 looked Cuenot 's results, for in mentioning the cross of a hetero- 

 zygous agouti with a yellow carrying black, he states "appar- 

 ently Morgan is the only one who has reported such a cross. He 

 obtained 4 yellows, 5 agoutis and 1 black." 



To return to Cuenot 's work; in 1907 he made a report on the 

 hereditary behavior of the white bellied agouti variety (gris a 

 ventre blanc) which he considers allelomorphic to yellow, agouti 

 and black. On page 10 in speaking of determinants he says: 

 "II y en a le meme nombre dans les races unicolores et dans la 

 race grise ; ces races different, non pas par la quantite de leurs 

 determinants mais par la qualite." This is essentially the idea 

 underlying multiple allelomorphism. Later in the same paper 

 he says of G, the agouti determinant . . il present un grand 

 nombre de mutations: G', N et J." (G' = white bellied gray; 

 N== black and J = yellow.) On page 13 he tabulates the vari- 

 eties, in order of their dominance, yellow, white-bellied agouti, 



