454 Vererbung, Variation, Mutation. 



portion of the eggs developed that some intermediate or maternal larvae appeared ; 

 (5) different cultures from one fertilization always gave the same type of inlieri- 

 tance. It seems tlierefore that conditions acting on the miliaris females before 

 the eggs matured affected their jjower of transmitting the specific characters to 

 the hybrid plutei, 



The paper includes detailed descriptions and excellent coloured plates of 

 plutei and young urchins of the three species and of the hybrids. U. miliaris 

 was reared from the egg to sexual maturity, and hybrid urchins are so far ad- 

 vanced that it is hoped they may become mature. There is also a füll biblio- 

 graphy and discussion of previous work which bears on the problems investigated, 



Doncaster. 



1200) Fryer, J. (\F., An Investigation by Pedigree breeding into the 

 polymorphism of Pai)ilio polytes Linu. In: Phil. Trans. Royal Soc, 

 Bd. B 204, S. 227—254, 1913. 



Papilio pol Dies has one form of male and three forms of female, (a) form 

 cyrus resembles the male, (b) form romulus resembles P. Jiedor, (c) form polytes 

 resembles P. aristolocJdac. The author carried out extensive breeding-experiments 

 in Order to elucidate the hereditär}^ relationships of these three forms. The me- 

 thods used are described, and notes are given on the life-history, manner of 

 pairing etc. In this connexion the Observation of most general interest is that 

 there is appreciable selection of mates by both sexes, but there is no evidence 

 that sight plays any part in it. Complete sterility v^^as frequently observed bet- 

 weeu certain individuals; males which were sterile v^^ith one female might be 

 fertile with another. 



In general, the experiments show that the romulus (Jiector) and polytes (ari- 

 siolochiae) forms of female may be classed togetlier as distinct from the cyrtis 

 (male form) females ; the difference between romulus and polytes depends on the 

 presence or absence of a romulus factor, romulus being a simple dominant to 

 polytes. Although the ratios are somewhat irregulär, the results seem fully to 

 justify this conclusion, and to show that the romulus factor may be carried by 

 the male. The female forms may therefore be divided into two groups ouly, 



(1) the cyrus (male form) type, and (2) the mimetic forms. It is tlien found 

 that cyrus females may produce (1) only cyrus 5 off spring, (2) cyrus and mime- 

 tic ?? in about equal numbers, or (3) only mimetic $$. Each of the mimetic 

 forms, however, may produce (l) cyrus and mimetic in about equal numbers, 



(2) cyrus and mimetic in the ratio of about 1 : 3, (3) mimetic $? only. From 

 these facts it is concluded that the mimetic form is determined by a factor H, 

 the absence of which causes the female to have the cyrus form. Males may bear 

 H, but always have an inhibiting factor P, which is absent in the female. Hence 

 males are of the Constitution Pphh, PpHh, PpHH, but owing to the action of 

 P all have the same form. Females are pphh [cyrus), ppHh, or ppHH (mime- 

 tic). All the off spring of a $ ppHH will be mimetic, since H is dominant, 

 $ ppHh will give equal numbers of mimetic and cyrus with male Pphh, or 

 3 mimetic to one cyrus with male PpHh, and a cyrus $ pphh will give either 

 all cyrus, half cytms and half mimetic, or all mimetic, according as the male is 

 Pjjhh, PpHh, or PpHH. The detailed results, of which an account is given, 

 are in general accord with this hypothesis. It is pointed out that this scheme is 

 in general agreement with that proposed by Baur for Jacobs on 's experiments 

 with Papilio memnon, but that the results are inconsistent with the schemes sug- 

 gested by de Meijere and Gold Schmidt. Finally, it is showu that the ratio 



