The determination of sex in animal development. 723 



condition" (in : Mitth. zool. Stat. Neapel, V. 5, 1884, p. 57.8). This con- 

 clusion, and subsequent attempts on the part of the writer to establish 

 it more firmly, have, except upon the part of the late Fritz Müller, 

 who fully endorsed it, attracted more discredit, and even abuse, than 

 anything else. Maupas cites the researches of various authors 0> 

 including Fritz Müller and W. M. Wheeler, but for some inscrut- 

 able reason my work upon Myzostoma is nowhere referred to by 

 him, although it furnished in part the pioneer-basis of his results, 

 which confirm, while naturally extending, my conclusions. The cit- 

 ation of Wheeler's work with the neglect of mine is curious, for un- 

 like my own the conclusions of the former are diametrically opposed 

 to Maupas' results. 



Maupas, at any rate, has no belief in the existence of the mira- 

 culous conversion of males into hermaphrodites, which under Wheeler's 

 views would daily happen. 



Something of the well - deserved honour, paid to Maupas' re- 

 searches upon the hermaphroditism of Nematodes by the Academy of 

 Sciences, Paris, is thereby reîlected upon my earlier pioneer-investi- 

 gations into the nature of hermaphroditism. And, ignoring the dis- 

 credit, and even the personal abuse, the latter have called forth, I 

 venture to deduce from the recognition given to Maupas' work a 

 compliment to my own. The high source of this only makes it all 

 the greater and more valuable. 



III. The supposed Influence of Fertilisation upon Sex. 



In other parts of* the present writing some of the evidences, 

 pointing to the absence of any influence of fertilisation upon the sex 

 of the subsequent offspring, are briefly referred to, and it is denied, 

 that the sex of an egg, destined to develop either after fertilisation 

 or parthenogenetically, can be influenced or altered by anything sub- 

 sequent to the period of the formation of the oocyte, which becomes 

 "the egg" by giving off the rudimentary sister-gametes, the polar 

 bodies. 



1) The priority of the discovery, that "rhermaphroditisme est 

 d'origine secondaire et la dioïcité l'état antérieur" is assigned by Mau- 

 pas to Yves Delage and Pelseneer (1. c. p. 594). Pelseneee's re- 

 searches were not published until 1895, while Delage's conclusion and 

 my own identical one appeared independently in 1884. My words 

 were "hermaphroditism, probably ^11 hermaphroditism, had its origin in 

 a unisexual condition". 



