260 Vererbung, Variation, Mutation. 



show atrophy, and tlie phenonienon is due eithei- to hereditary transference of 

 the feraale characters, or to arrested development. 



In the hj-brid pheasants dealt with, there was a great preponderance of males, 

 and it is shown that this cannot be due to selective mortality, unless at an ex- 

 ceedingly early embryonic stage. It is evident therefore that in these hybrids 

 successful fertilization occurs most frequently between gametes which will form, 

 a male zygote rather than those which wdll form a female, so that the experi- 

 raents give evidence of the existence of selective fertilization. 



Doncaster (Cambridge). 



816) Weiitworth, E. N. (Iowa, College), Inheritance of Mammae in Duroc 

 Jersey swine. In: Amer. Natural., Bd. 47, S. 257 — 278, 1913. 



In the breed of swine studied, the number of mammae varied usually from 

 10 to 12, while in Tamworths and Berkshires Bateson found the usual number 

 to be 13 — 15. In addition to Variation in the number of pairs there are two 

 asymmetrical types of nipple variations. As the number of mammae increases 

 the ratio of asymmetrical to symmetrical patterns also increases, but there is no 

 evidence that asymmetry is unilaterally inherited. The correlation between mother 

 and offspring as regards number of mammae is small — about 0,2626 — but there 

 is distinct inheritance of the tendency to produce a greater number of pairs. The 

 paired rudimentaries to the rear of the inguinal pair in the male are inherited 

 in Mendelian sex-limited fashion, but no definitely mendelizing units were found 

 in the abdominal mammary series. Gates (London). 



817) Fog'le, P. E., Transmission of Color and Color Markings in 

 Hereford-Shorthorn Grosses. In: Amer. Breeders' Mag., Vol. III, No. 3, 

 S. 201—204, 1912. 



The author has tabulated the results of transmission of color and color 

 markings as they have appeared in crossing Hereford with Shorthorn cattle, 

 grouping the colors under five separate heads: Red, roan, spotted, white, rebody 

 with white face. In the color markings he records particularly the occurrence 

 of eye circles and spot on nose. Pearl (Orono). 



818) Doncaster j L. (Cambridge, University), On sex-limited inheritance 

 in Cats, and its bearing on the sex-limited transmission of certain 

 human abnormalities. 



A Short summary is given of our knowledge of the inheritance of sex-limi- 

 ted affections in man, and it is pointed ont that the complete elucidation of 

 these is made difficult by the impossibility of distinguishing the transmitting 

 females, except by the fact that they have affected sons. In the Cat the orange 

 colour is sex-limited in the male, being commonly transmitted only to the female 

 offspring. A female which receives orange from the male parent and black from 

 the female is tortoise-shell; the "transmitting female" (tortoise-shell) is thus 

 distinguishable from the "non- transmitting" (black). Evidence is given that 

 orange males mated with black females may have some black daughters, indi- 

 cating that the sex-limitation of the transmission of orange by the male is not 

 absolute, and more rarely tortoise-shell males are produced. The data are not 

 yet sufficient for the formulation of a complete scheme of colour-inheritance in 

 cats, but when the case is thoroughly worked out, it will probably provide a So- 

 lution of the disputed problems with regard to sex-limited inheritance in man. 



