396 Referate. 
The black barb carries both the dominant factors, and the white fantail neither 
of them. The normal redistribution of characters in F, results in a certain 
proportion of birds which contain the colour factor but are without the factor 
for black. These are the reversionary blues which, owing to the dominance of 
black, can only appear in the F, generation from such a cross as this. 
The numbers though not large accord on the whole fairly well with Men- 
delian expectation, but heterozygous blues crossed with whites gave a curiously 
aberrant result. Where equality is the simplest expectation these matings 
resulted in 13 blues and 28 whites. The author points out that this excess of 
whites is most striking where the white is the 3 parent. Such matings gave 
8 blues and 21 whites as against 5 blues and 7 whites where the 3 parent was 
blue. It is suggested that the excess of recessives which occurs when the 
white goes in from the 3 side may possibly be comparable with the curious 
differences that obtain in the production of the recessive red eye in cinnamon 
canary crosses accord ng as the 3 or the ° cinnamon is used as a parent. 
In certain of the barb-fantail crosses reds appeared in F, and the author 
brings forward evidence to shew that red is recessive to blue or black. Being 
a coloured form red behaves as a dominant towards whites which are not 
carrying blue or black. But, as is only to be expected, whites which carry 
black give blacks when mated with reds. 
A few experiments were made with the nun pigeon but no reversionary 
blues were produced. 
A cross between the white tumbler and the white fantail gave an inter- 
esting result. The F, birds were either pure white or shewed a few coloured 
feathers (’’ticked whites“). Two of the latter bred together gave whites, 
ticked whites, and tricolors. The appearance of these coloured birds in F3 
points to the white tumbler being a dominant white, i. e. a coloured breed 
in which a dominant colour-inhibiting factor prevents the apparance of the 
colour. The cross with the recessive white leads to the separation of the 
factors for colour and colour-inhibition and consequently to the production 
of some coloured birds in F,. The case would appear to be similar to one 
that has been more amply worked out in poultry. 
The author has made some investigations into the inheritance of the 
three forms of iris, white, orange, and black, which were met with in the 
course of the experiments. While admitting the necessity for further ex- 
perimental work he brings forward evidence to shew that white behaves 
as a simple dominant to black, and suggests that black will be eventually 
found to be recessive to orange, and that orange may be recessive to white. 
A point of considerable interest lies in the marked correlation between the 
black iris and white plumage, and, to a lesser degree, between black 
plumage and the white iris. 
Pigment in the beak and claws would appear to be correlated with 
certain types of plumage, and in this way behaves as a simple dominant 
to the absence of such pigment. RE Ca ea timiokentas 
Lang, Arnold. ,,Uber“die Bastarde von Helix hortensis Müll. und Helix 
nemoralis L., eine Untersuchung zur experimentellen Vererbungslehre.“ 
Mit Beiträgen von H. Bosshard, P. Hesse, E. Kleiner. — 120 S., 
4 lithogr. Tafeln. Jena, G. Fischer, 1908. 
(Nebst ergänzenden Bemerkungen aus Lang, ‚Über Vorversuche zu Unter- 
suchungen über die Varietätenbildung von Helix hortensis Müll. und 
H. nemoralis L.“ — Jenaische Denkschriften XI., Festschrift für 
E. Haeckel, 1904.) 
