8 Varietäten, Descendenz, Hybriden. 



she found that the iris was heavily, and the choroid slightly, pig- 

 mented with chocolate. 



Of pink-eyed mice, the albino has apparently no dark colouring 

 matter either in the eye or in the coat. The author believes how- 

 ever that a white substance, of the nature of a pigment, is present 

 in the hairs. In pink-eyed mice with coloured coats, the eyes are 

 only apparently unpigmented; the author has found that sections of 

 such eyes examined under the microscope reveal slight pigmentation 

 in both the iris and the choroid. 



Dense and Dilute Colorations. Pp. 44 — 49 of the report 

 deal in detail with the experiments relating to the inheritance of 

 the dense and dilute conditions of the various pigments. Without 

 going into detail here, it may be mentioned that the results very 

 fully bear out the expectation based on the scheme of factors adopted 

 by the author and given above. 



Piebald mice. Like Cuenot and Allen, the author has met 

 with mice in which the piebald condition is recessive to the self- 

 colour. Albino mice may carry the determinant for self-colour (in 

 which case a cross between a piebald and such an albino gives 

 only self-colours in F x ) or may be without it. Albino mice of the 

 latter kind mated with pure self-colours give only self-colours in F x ; 

 but in F 2 self-colours, piebalds and albinos are obtained. 



But in addition to the recessive piebald, the author has met 

 with mice in which the piebald character behaves as a dominant. 

 The mice of this class have all been derived from one mating. Four 

 of the descendants of these mice were mated with homozygous seif 

 mice, and gave 8 selfs and 13 piebalds. The piebalds were inter- 

 mated 8 times and gave 12 selfs and 44 piebalds. Piebalds descended 

 from the same union through albinos show again that the piebalds 

 are able to produce self-coloured mice. Piebalds, selfs and albinos 

 were produced from such matings, the albinos, however, being in 

 distinct excess of expectation. Other experiments illustrating the same 

 phenomenon are given in detail (p. 51) and the author concludes 

 that there are, genetically, two distinct classes of piebalds, which to 

 the eye are indistinguishable. 



Unconformable case. One case occurred for which the 

 author is unable to offer an explanation. A black doe was bred by 

 mating a blue with a black, both parents being homozygous, as was 

 shown by their other matings. The black doe so obtained was mated 

 with five different albinos, One of the albinos was descendent from 

 the dominant piebald race, and the union of the black doe with this 

 albino gave 3 albinos, 4 chocolates and 1 chocolate-and-white piebald. 

 The other matings resulted in 21 blacks. The albino was mated with 

 two other homozygous blacks and gave all blacks; and mated with 

 a homozygous chocolate gave 6 chocolates. 



At the end of the paper the author gives a list of the different 

 kinds of mice used. R. P. Gregory. 



Wheldale, M., The Colours and Pigments of Flowers, 

 with Special Reference to Genetics. (Roy. Soc. Proc, 

 Ser. B. LXXXI. p. 44—60. 1909.) 



The investigations were undertaken with a view to being of 

 assistance in the Interpretation of the phenomena observed in the 

 inheritance of flower-colour, an attempt being made to classify the 

 pigments and at the same time to ascertain whether there is any 



