BATESON AND PUNNETT 



The result discloses a distinct excess 

 of singles and peas, together with a 

 deficiency of r.p.s. Examination of the 

 table shows that whilst the result in 

 certain cases (e.g., Experiments 201, 

 205, 216, 245) fits closely with ex- 

 pectation, it is in other cases far re- 

 moved from it. Thus in Experiment 

 204 we should have expected not more 

 than 2 singles, whereas the actual num- 

 ber is 10. Yet the subsequent Experi- 

 ments 212 and 300 prove that the 9 

 was then giving off all four sorts of 

 gamete in equal numbers, whilst Ex- 

 periments 208 and 303 show that the 

 same was also true of the c? . It is con- 

 ceivable, of course, that the numbers 

 in Experiment 204 may be the result of 

 chance, but, having regard to the fact 

 that wherever any serious disturbance 

 of the ratio 9 : 3 : 3 : 1 occurs it is 

 generally accompanied by both excess 

 of singles and deficiency of r.p.s., we 

 are more inclined to attribute such 

 aberrations to the presence of some 

 disturbing circumstance hitherto un- 

 determined. 



''Extractecf Combs jrom Mating 

 r.p. X ^-P- 



Singles "extracted" from the cross 

 r.p. X r.p- were mated together in Ex- 

 periments 209, 210. 247, "and 248. Of 

 the 144 chicks resulting, all were 

 single. 



Seven extracted roses were tested, 

 with the result that one turned out to 

 be homozygous (Experiment 273) and 

 the rest heterozygous (Experiments 

 246, 263 to 266, and 274). With single 

 combed S s. these 6 birds produced 

 176 chicks, of which 92 were single 

 and 84 rose. Extraction has clearly 

 no influence upon the behaviour of 

 rose and single combs. 



An extracted $ pea-combed bird 

 produced (in Experiment 230) 2 

 singles and 3 peas with a Br. L. 9 . In 

 Experiment 231 an extracted pea- 

 combed 9 gave, with an s.c. S , 5 



53 



singles and 8 peas. In Experiment 228 

 an extracted p.c. S was bred with 3 

 extracted p.c. 9 s., and gave 20 singles 

 to 34 peas, the expectation being 13*5 : 

 40*5. Such an aberration from the ex- 

 pected ratio may easily be the result 

 of chance, though it is possible that 

 it may be due to the prevalence of 

 intermediate pea-combs. 



Intennediate Pea-combs.— In certain 

 families where the pea-comb was con- 

 cerned, heterozygote (p.s.) birds oc- 

 curred with some frequency showing 

 so little of the pea character that as 

 young chicks they could easily be 

 taken for singles. The median ridge is 

 very high, approaching the single 

 comb, whilst the lateral ridges are 

 much reduced. Such a comb requires 

 very close scrutiny in the newly 

 hatched chick to distinguish it from a 

 single. In one case such a bird, re- 

 corded as a single when a chick, 

 evenutally grew up with one of these 

 intermediate pea-combs. Experiments 

 with reference to the nature of this 

 comb are still in progress, and until 

 they are complete we propose to defer 

 our detailed account. We have alluded 

 to the case here because it may have 

 some bearing on the excess of singles 

 in Experiments 231 and 357. At the 

 time of that experiment we had not 

 fully grasped the distinction between 

 the intermediate pea and the single 

 comb, and it may very well be that 

 some of the combs then recorded in 

 certain families as single were in reality 

 of the intermediate type. 



The Malay Comb 



In the last Report (p. Ill) we drew 

 attention to the paradox that real rose 

 and single combs are not known to 

 occur among Malays when bred pure, 

 and we suggested as a possible explana- 

 tion that the $ s. only are capable of 

 producing all four forms of gamete. 

 In a subsequent note (p. 112) we al- 

 luded to a 9 Malay which was re- 



