116 Mr. G. P. Mudge. On the Hereditary | | May 8,. 
results, 2.¢., experiments 34 and 37, where albinoes appeared in a cross when: 
one of the parents is described as black. 
Since the black parent was the same in both experiments, and its parents 
were unknown, it is not improbable that it was an “Irish” a, and not a. 
true black. If we make this assumption and accept the conclusion as to the 
nature of the Cr 6 @ given in this paper (Conclusion 7), then the results of 
Doncaster’s experiments 34 and 37 are in accordance with prediction. 
6. The “Irish” “5d” type is a heterozygote. Two zygotic forms have: 
probably been experimentally recognised, ae, of the composition CegBSsP” 
and CgBSsP (104—107). 
With regard to this conclusion, the first symbolic representation confirms. 
that of Doncaster, while the second is new. 
7. That the “Irish” “a” type is perhaps of the composition CegBSP. 
At present there is no direct evidence of this; but in the possible theoretical 
gametic combinations (supra, pp. 103 and 109) such a composition occurs.. 
The evidence shows that the “Irsh” 6 always carries piebald and s, 
and this being so, the composition CcgBSP can be ascribed to the 
“Trish” a form alone. Some of Doncaster’s experiments (15, p. 225, 
experiments 35 and 63) show that the “Irish” “a” does, in some cases, 
carry albinism recessive. 
Hence his own conclusion, that the Cr 7 is only an extreme type of 
Cr 6a@ and is not a separate variety, needs for the present to be accepted. 
with hesitation. My work indicates that the Cr 7 is homozygote for black 
(see 5). The above considerations suggest that the two varieties are: 
distinct. And, taken in connection with Conclusion 6, suggests that both 
“Trish” a and “Irish” 0 are heterozygotes. 
With regard to the composition CegBSP ascribed to the “ Irish” a, there is: 
to be remembered Doncaster’s conclusion, which I endorse, that the 
“Trish” @ and the Cr 7 have given no evidence that they carry P. But: 
there is nothing inconsistent between this conclusion and the symbolic 
representation of this form, because S and P are not allelomorphic to each 
other, and, therefore, though P may be present, it cannot be manifested so, 
long as S is also present in the same gamete or zygote. Evenif the “Irish” @ 
contains P, and it is crossed with an albino carrying P, no piebald forms. 
will be expected in the F 1 generation, because it (the “ Irish” a) also carries S.. 
Neither are they expected if “Irish ” a x “ Irish” a. 
Piebald forms cannot appear until s is introduced into the “ Irish” gamete: 
or zygote. The evidence indicates that when this is done the “Irish” 6} 
zygotic form is produced. It seems impossible, therefore, to obtain direct, 
experimental evidence that the “ Irish” a carries P. 
