Xo. 641] SHORTER ARTICLES AND CORRESPONDENCE 567 



or he would not say tliat in that case I "would not so casily 

 produce a symmetrical V., curve." 



That he has not assimihited the sif,mificance of the intor-play 

 of plus-acting and miruis-actinnr factors is shown by his que's- 



The curves in my Vig. 1 are an adequate answer iu this (jiiestion. 



Finally, it seems hardly necessary to point (nii tlie ina(le(iuacy 

 of the ease of the Blue Andalusian fowl, as a piooi tiiat incciual- 

 ities in {jenotypic variation are not masked by thietatKins when 

 the amount of fluctuatiiin' variation is lar-e m e.mipansnii with 



determined by the numerous factor conilnnat ions pniatively in- 

 volved in the several examples cited in ( a^Ile■s oi iumal paper. 



GENETIC TERMl XOL()( ; Y 



The genetic terms recently proposed by (i. 11. kSIiuII' seem 

 to supply a real need. Their general use would certainly tend 

 to reduce both the danger of am])igui!y and tlu> need ioi- cum- 

 bersome descriptive phrases. Pi'ohahly a tew aiiditional nunier- 

 ical terms, such as dizygous and //•/:;/</////>.- woiiM also W usefid. 

 Some existing equivalents have an obvious disadvania-r' with 

 respect to compounding; the compound I ndi mninsnnni! . tor ex- 

 ample, could not replace trizygous ("depeiKh nt on ihree paim 

 of chromosomes"). Monozygous and ph. lozin/ci's, alriiou<:h often 

 interchangeable with linked and unlinked, sliould he useful; 

 the latter, for example, to characterize genes tliat are located in 

 several pairs of chromo.somes but are not all necessarily uidinked 

 with each other. These words are so interrelated amontr them- 

 selves, and so closely related to tei-ms in general use. that all 

 their advantages can ])e realized Avitli little etVort. 



Shull suggests tluit it is nine "to abandon the use oi -Monde- 



