52 H. D. GOODALE. 



thus: Male mc mc, gametes mc, mc, female mc M, gametes 



d" 9{x) cf ? ix) 9 (x) $ (x) 



mc, M. The only matings to be regarded as possible are mc by 



9{x) 9{x) 9(x) 



M and mc by mc. 



9W 9(x) c? 



The X in parenthesis is given as an alternative mode of repre- 

 senting sex by the jc-element. This mode of representation would 

 bring the experimental results into line with Guyer's discovery 

 of an accessory in fowls. 



The modifier assumed can hardly be specific for every type 

 of dimorphism, else in cross breeding the later generations of 

 females should show various modifications of the original female 

 type. Of this there is no evidence. The modifier may, of course, 

 be femaleness itself, in which case a somewhat different mode of 

 representation should be employed. 



It is obvious that Guyer's discovery of an accessory in fowls is 

 contradictory to the results of experimental study which indicate 

 the correctness of the Bateson-Spillman theory of sex in fowls, 

 unless selective fertilization is assumed. Even if this be done, the 

 male color obviously cannot be transmitted by the idiochromo- 

 somes. There is, of course, the possibility that the rv-element is 

 not a sex determiner at all, but merely a further indication of sex 

 dimorphism. On the other hand the discovery of cocks which in 

 cross breeding transmit some character to their female offspring 

 only, would disprove the Bateson-Spillman theory. Hagedoorn 

 seems to have found such a case, but he does not seem to have 

 noticed its implications. A reexamination is desirable. 



Before proceeding further, a brief account will be given of 

 some modifications of sex. 



Braem, while studying regeneration, removed the last 22 seg- 

 ments of 35 in a female Ophryothrocha. Later he found that the 

 ova in the anterior sections were degenerating and spermatozoa 

 developing. Hermaphrodites often occur in Ophryotrocha, but 

 in these the male germ cells always develop first, exactly the 

 reverse of the present case. 



During the past summer, my attention was attracted to certain 

 changes in sex in maize, which is monoecious. The maize plant 

 consists of a single stalk, at the apex of which is the tassel bearing 



