HERMAPURODITE OENITA^LTA OP THE CODFISH. 547 



overthrown or, at least, challeuged ou tolerable grounds. Bal- 

 four and Sedgwick were the first to clearly show that the 

 Mlillerian duct of the Amniota might be (chick) a compound 

 structure, for the first part of its course split off as a solid 

 and backwardly-exteudiug rod " from the outer or ventral 

 wall of the WoMan duct." Concerning the " posterior part 

 of its course," Balfour wrote that "its growing point lies in a 

 bay formed by the outer walls of the "Wolffian duct, but does not 

 become definitely attached to that duct. It seems, however, 

 possible that, although not actually split off from the walls of 

 the Wolffian duct, it may grow backwards from cells derived 

 from that " {loc. cif. p. 592) *. 



Conspicuous among the post-Balfourian researches afore 

 alluded to are those of Milhalkovics t, Jungersen +, Wieder- 

 sheim §, and others, which have revealed the fact that the 

 Mlillerian duct of the Amniota is formed, mainly if not entirely, 

 as a derivative of the peritoneum, wholly independent of the 

 Wolffian duct, arising far forwards and gradually extending 

 back. Jungersen's extensive inquiry was especially directed 

 towards the Teleostei. He found that the genital duct of the 

 female arises as a peritoneal derivative, formed late — that is, sub- 

 sequently to the differentiation of the genital gland, with the 

 investment of which it becomes subsequently connected ||. 

 E-elying upon his discovery of this independent origin he argues, 

 from analogy to the independent origin of the Mlillerian ducts 

 of the Amphibia and Amniota, in favour of an homology between 

 the two, and shows If that the genital duct of the female Teleostean 

 may be looked upon as either partially or entirely homologous 

 with the Mlillerian duct proper, in accordance with different 

 views which he formulates. 



Jungersen has observed that whereas in the females the 

 genital duct arises independently of the gland, in the males the 

 two appear to be from the first continuous ; and he urges 

 this as a fundamental distinction between the sexes. The 

 leading variations in the structure and relationships of tlie fully 



* Cf. also Quart. Jourii. Micr. Sei. vol. xiv. n. s. p. 9 (1879). 



t Month. Inlernat. Jom-n. of Anat. & Hist. vol. ii. p. 284 (1885). 



\ Arbeit, a. d. Zool. Zoot. Instit. Wiirzburg, Bd. ix. p. 89 (1880). 



§ Archiv f. mikr. Anat. Bd. xxxvi, p. 410 (1890). 



II Loc. cit. pp. 179 ct seqq. ^ Loc. cit. pp. 192-2W. 



LINX. .lOURN. — ZOOLOGV, VOf,. X'vlll. 39 



