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Show 84 MR. W BATESON ON COLOUR-HEREDITY [May 26, Mating. Offspring. (34) bl.?D2(Dxa)(DR) X blw.<?a (DR) 2bl. lbr. 2blw. (35) B Xw.<?e 1 bl. 1 br. 3blw. 2 w. (4eaten). (36) „ Xbrw.<?CM(DD)(C2Xa) 3 bl. 2 br. 1 blw. (3 eaten). (37)br.?D3(DX«)(DR)Xblw.<?a(DR) 2 bl. lbr. 3w. (38) „ Xbrw.<?y(DR) 3 br. 2 brw. 3w. (39) „ Xw.<?e 1 bl. 1 blw. 1 brw. 2 w. (40) w.?B2-!(B-Xa) X blw. <? a (DR) ... 2 blw. 3w.(3eaten). (41) „ X „ .- 5W- (42)blw.?C1-2(CiXa)(DR)Xblw.^a(DR) ... 7 blw. (43) „ X ... *Ww. 2w. (44) blw.?C1-3(C1Xe)DRXbrw.<j7(BXa)(DR) ... 7 blw. lw. (45) blw.?D2-3(D2Xa) Xblw.c?a(DR) ... 5 blw. (46)blw.?D3-3(D3X«) X brw. c?C>2(C2Xa)(DD) 1 bl. 1 br. 1 blw. (1 died). (47) bl.?D1-1(D1Xa)(DR)X w.c?e 1 bl. 2 blw 2w. (48)blw.?C1-2-1(C1-2Xa)X blw.a'a(DR) ... ... 5 blw. (49) blw.?C1-2-2(C1-2Xa)X blw.<?a(DR) ... ... 7 blw. (50) b l w . ^ C ^ - H C ^ X ^ X blw.<Ja (DR).. * bllwv. The mice originally introduced were 5 albino females, 2 albino males, 1 black-and-white male, and 1 black-and-white female, all of unknown extraction. Several albinos were produced in the experiments. Mated with albinos they gave albinos only (41 in all). The original blw. S « was heterozygous, containing albino, but the blw. £ C probably did not, though"the figures are insuificient for proof. Both of the original blw. on mating with albino gave rise to some brown or brown *- and-white offspring, and were probably giving off gametes of this nature. All such specimens were alike in tint except one which was distinctly lighter. The families of the albino D (expts. 10-14) are especially interesting; for, as Mr. Parsons pointed out to me, all the 13 coloured offspring by two different broken-coloured males, one brw., the other blw., were se£/"-coloured, brown, or black. This result resembles one obtained by Castle (5. p. 542), but the suggestion that such a pied individual is a mosaic which throws self-colour gametes is not readily applicable to this case. For here the peculiarity evidently lies in the gametes of the individual albino, since with other albinos the same males gave pied offspring. As Castle commonly obtained such self-coloured mice from albinos crossed with pied, it is likely that the peculiarity may belong to certain strains of albinos. The detailed account of his experiments, which is promised, may perhaps give an indication on this point. Parsons' cases give besides some indications as to the ratios of the gametes. It will be seen that the relation of brown to black is not merely that of dominant and recessive, for either may give either. Nor can it be supposed that the brown is a mere heterozygous form. Each colour, whether self or pied, may be dominant over albino, and the figures show pretty clearly that in * Microscopical examination of a specimen kindly sent by Mr. Parsons proved this colour to be " chocolate." |