COMBS OF FOWLS 183 



pigmentary constitutions. Thus, a negro having a 

 composition of CcD^d^d^d^, when crossed with any 

 European, would give a mulatto offspring, the members 

 of which, married to an European, would produce Euro- 

 peans as well as mulattoes. The divergency, therefore, 

 between the two sets of evidence is probably apparent 

 and not real. The mulattoes of the West Indies, it is 

 conceivable, may have one zygotic composition, perhaps 

 similar to that which we gave on page 179, while some 

 or all of those of the other island have another, similar 

 to that just given. In marriages with Europeans, the 

 one kind will not be expected to beget Europeans 

 among its offspring and the other wiU. 



(3) Variation in the Single Combs of fowls. 

 Some Mendelian Comments. 



In a recent number of " Biometrika"* there appears a 

 paper under the joint authorship of Dr. Raymond Pearl 

 and Miss Maud Dewitt Pearl, entitled " Data on Variation 

 in the Comb of the Domestic Fowl." The authors have 

 propounded a number of questions, but the central thesis 

 turns upon the one question as to whether single combs 

 or their various grades breed true. And, if they do 

 not, to what extent do they vary. As the authors 

 point out, " nothing is more certain than that all 

 single combs are not ahke in respect to any feature 

 whatsoever, even including their singleness." While 

 we are not disposed to question the statements in 

 this sentence as a whole, the last clause of it calls 

 for comment. It implies that there are forms of combs, 

 which are neither single, nor pea, nor rose, but a sort 

 of blend of single with pea, or single with rose. The 

 occasional existence of such apparently transitional 

 forms, is well known to the Mendelian, and the explana- 

 tion of them is given later in this article (infra p. 193). 



* Vol. IV., Part IV. 



