Vererbung, Variation, Mutation. 313 



7. Zeitliches Auftreten der Dotterchromatophoren. Auch hier zeigen die 

 Hybride intermediäres Verhalten. 



Während also bezüglich solcher Pigmentierungsunterschiede zwischen heteroclitus- 

 und }Hf(/«;/s-Embryonen, die auf Vorhandensein, bzw. Fehlen bestimmter Merkmale be- 

 ruhen, deutliche Dominanz des einen und zwar_ meist des /jeterocZiiws-Charakters bei den 

 Bastarden zu konstatieren ist, zeigen letztere ein intermediäres Verhalten, sobald es sich 

 um zeitliche Beziehungen der Färbungscharaktere zu gewissen Entwicklungsstufen handelt. 

 Daß dies Verhalten unter Umständen nur ein scheinbares sein kann, hat sich bei näherer 

 Analyse eines der hierhergehörigen Fälle (Auftreten der Chromatophoren des Kopfbezirkes) 

 ergeben und trifft vielleicht auch für die übrigen zu 



Sofort nach dem Ausschlüpfen beginnen die auf verschiedener Pigmentierung be- 

 ruhenden Unterschiede sich zu verwischen, so daß nach wenigen Monaten die 3 Formen 

 (die Bastardembryonen aus mrt/rtZiS-Eiern schlüpfen nicht aus) gleiche Zeichnung — 3 — 7 

 schwarze Querbinden — aufweisen. M. Daiber (Zürich). 



873) Doncaster, L. (Cambridge, University), Notes on the Inheritance 

 of colour and other Characters in Pigeons. In: Journal of Genetics, 

 Vol. 2, Nr. 2, S. 89—98, 1912. 



Leg-feathering proved to be partially dominant over its absence: the ex- 

 tent of the feathering in lieterozygous birds is somewhat variable. The fantailed 

 character was almost completely recessive in the first-cross with a normal- tailed 

 bird, and did not reappear among 23 young reared in Fg. As regards colour- 

 characters, the white fantail appears to carry a factor for blue with dark wing- 

 bars, and a white extracted in Fg from the cross white fantail by red was shown 

 to be heterozygous for the factor for red. White Pigeons, therefore, like albino 

 mammals, can bear the factors for colour. Black by white fantails gave F^ 

 young which were patched, black-and-white. These paired together gave no 

 blacks in Fg. but pure blacks were produced by mating the darkest Fg bird with 

 an F;l in which the black preponderated. It is suggested that these results can 

 be accounted for on the assumption that at least two pairs of factors are con- 

 cerned in the production of fully black birds. Doncaster (Cambridge). 



874) Staples-Browne, K., Second report on the Inheritance of colour 

 in Pigeons, together with an account of some experiments on the 

 Crossing of certain races of Doves, with special reference to sex- 

 limited inheritance. In: Journal of Genetics, Vol. 2, Nr. 2, S. 131 — 162, 

 1 Plate, 1912. 



Describes in detail the results of matings of blue and silver Rock doves to 

 each other and to whites, of Silver Owl and Black Fantail; of Blue Dragoon and 

 Dun Carrier, and matings between Turtle doves and Collared and while Barbary 

 doves. As regards the four colours Black, blue, dun and silver, it is found that 

 these are due to combinations of two pairs of characters. If B is the factor for 

 black, B a factor for density, black \s BB, silver hd. Blue is probably Bd, 

 dun hB, but it is possible that dun is dilute black {Bd), and blue IB. The 

 most important results are those dealing with sex-limited inheritance. The crosses 

 between black, blue, dun and silver are not yet complete, but it was found that 

 silver $ X black J' gave all offspring of both sexes black, while the converse 

 cross black $ X silver cT gave black males and dun females. The black female 

 therefore shows sex-limited transmission of the black factor, transmitting it only 

 to her male offspring, as has been found with other characters in fowls and in 

 Abraxas. In the crosses between Turtle and Barbary doves (Tiirtur turtur, T. 

 risorius and the white variety of T. risorius), it was found that white risorius ? 

 X turde c? gave only coloured offspring of both sexes, but that the converse 

 cross Turtle $ X white risorius d* gave dark males and white females. Since the 



