Referate. 155 
erbten zwei, die eine Verwandtenehe eingingen, die Anomalie auf einen 
Teil ihrer Kinder und von letzteren hatte eines, das keine Verwandtenehe 
einging, ein normales und ein haararmes Kind. Eine Verwandtenehe eines 
normalen Bruders mit der Anomalie Behafteten ergab nur zwei normale 
Kinder. Fischer weist darauf hin, daß letzterer Fall und das plötzliche 
Auftreten der Anomalie nicht mit der Annahme der Dominanz der Haar- 
armut stimmt. Bei der geringen Größe der einzelnen menschlichen Familie 
darf man aber nicht in jedem einzeln Fall eine sichtbare Kontinuität der 
Vererbung erwarten, außerdem stehen die Erbqualitäten der Ehegatten 
und der Ahnen zu wenig fest, um ein Urteil darüber zuzulassen, ob 
Dominanz, Racessinität oder ein komplizierter Polyhybridismus vorlag oder 
die Eigenschaft als Mutation auftrat. Weinberg-Stuttgart. 
Sollas, I. B. J. Inheritance of colour and supernumerary mammae in guinea- 
pigs, with a note on the occurrence of a dwarf form. Rep. Evo]. Comm. 
Roy. Soc. V, pp. 31—79, I plate, 1909. 
In the present paper Miss Sollas gives an account of five years ex- 
periments with guinea-pigs, and from the result of numerous crosses she 
is able to provide a scheme of the gametic factors concerned. Apart from 
albinism, which is shewn to be recessive to the fully coloured forms, the 
various types may be interpreted in terms of the following four factors, viz., 
G, a factor determining ticking of the hairs. 
Bear by; 5 black pigment in the eye and skin. 
Barack, Ps red pigment in the hair, and red and chocolate 
pigment in the skin and eye. 
(El En as chocolate pigment in the hair, skin, and eye. 
The coloured forms fall into two series, a dark-eyed series and a ruby- 
eyed one according as the factor for black pigment is present or absent, 
and they may be expressed in terms of the above factors as follows: 
Agouti, GBRCh. Cinnamon, GbRCh. 
Dark-eyed | Black, gBRCh. Ruby-eyed ! Chocolate, gbRCh 
| Red, gBRch. | Red, gbRch 
Further, any one of these six forms may exist in a dilute condition, 
and such dilute forms behave as recessive to the corresponding form with 
intense pigmentation. 
The paper also deals with the inheritance of characters other than 
colour, viz. supernumerary mammae and dwarfness. Supernumerary 
mammae may be present in either sex. More than one additional pair 
was never observed, and in many cases an additional mamma was present 
on one side only. The heredity of this character resembles that of the 
extra toe in guinea-pigs and poultry in apparently shewing neither dominance 
nor recession. Thus the normal offspring of abnormal parants may give 
some abnormal young. 
During the course of the experiments a peculiar dwarf form appeared 
which was remarkable in the shortness of the thick-set body, the shortness 
of the limbs, and the unusual form of the head. These dwarfs generally 
died young and the author did not succed in obtaining offspring from 
any of them. The proportions in the families where they occurred, 74 
normals to 25 dwarfs, point to the condition being recessive. It is however 
remarkable that the condition is much more frequently associated with 
the male sex, for of the 25 dwarfs no less than 20 were males. An illus- 
brated description of the characters of these dwarfs is given in the paper. 
R. C. Punnett. 
