73 Vererbung, Variation, Mutation. 



Long- and short-winged flies were also tested in this way and the former 

 found more viable. Gates (London). 



181) Morgan, T. H., Simplicity versus adequacy in Mendelian for- 

 mulae. In: Amer. Natural., Bd. 47, S. 372—374, 1913. 



A reply to certain criticisms of Castle regarding a recent Suggestion for 

 the reformation of Mendelian nomenclature. Morgan points out the reasons why 

 a dual set of Symbols for each character is necessary. In this scheme the small 

 letters stand for the factors (thus p for pink and b for black in DrosopJiüa) while 

 the allelomorphs of these factors in the normal flies, which are dominant, are 

 represented by the corresponding capitals. The further Suggestion is added, that 

 the better standing for a "dominant mutant factor" be primed (D'E'F'). Their 

 allelomorphs would then be d'e'f'. Gates (London). 



182) Hadley, P. B. (Rhode Island, Agric. Expt. Station), The presence of 

 the barred plumage pattern in the white leghorn breed of fowls. 

 In: Amer. Natural., Bd. 47, S. 418—428, 6 Fig., 1913. 



White Leghorn males were crossed with several females belonging to black 

 breeds, including Black Hamburg, Black Minorca, Black Java and Black Spanish. 

 Black Hamburg $ X White Leghorn c? gave in F^ (110 birds) white off spring 

 all of which, however, showed fleckings of black, several having a few barred 

 or partly barred feathers. The white of White Leghorn is thus a "dominant" or 

 "inhibiting" white. The F^ contained blacks, grays, whites, splashed whites and 

 barred birds. The facts are explained on a Mendelian basis as follows: 



The White Leghorn d" contains an inhibitor (I) and a factor for black (N), 

 also a colour factor (C), and is homozygous for the absence of the female sex 

 factor (F). It is further assumed that the barring factor, B, is repelled by F. 

 The Black Hamburg $$ are assumed to contain C and N and to be heterozygous 

 for F. On this hypothesis every 16 Fg birds should contain 12 whites, 3 barred 

 and 1 black. The whites should be equally divided between the sexes, of the 

 barred birds there should be 2 cfd* to 1 $ and the black should be female. One 

 of the barred cTd" should moreover be homozygous for barring, while the other 

 cT and the $ should be heterozygous. Other birds should carry the barring factor 

 latent, and will be homozygous or heterozygous for I. 



The results, so far as they go, seem fairly in agreement with the hypo- 

 thesis. Gates (London). 



183) Ooodale, H. D. and Morgan, T. H., Heredity of tricolour in guinea- 

 pigs. In: Amer. Natural., Bd. 47, S. 321—348, 143 Fig., 1913. 



Tricolour guinea-pigs have red, black and white in their roots, there being 

 much Variation in the area occupied by each colour. This leads to various types 

 of Spotting, and the results deal with the behaviour of the various types of 

 tricolour when mated with each other. A careful series of records was kept, 

 showing the exact distribution of the pigments in all the coats. The data are 

 much too complex to record here, but the results, which are in part corrobora- 

 tive of those of Castle, may be summarized. Uniform coat X spotted gave 

 only uniform in Fj, with a variable Fg generatiou. 



Castle's explanation rests on the hypothesis that black and white are irre- 

 gularly distributed, while yellow is always uniform in distribution. Morgan is 

 iuclined to assume many factors for various degrees or kinds of Spotting, and 

 apparently thinks that mere Variation in somatic distribution of the areas in 



