550 PliOr. G. 13. HOWES Olf SOME 



Huxley sbows, lamelligerous and freely pendent, and reflected 

 ventro-externally ; while its duct is incompletely tubular and 

 directly continuous with the mesovarium. The ducts of opposite 

 sides pass back, converging as they do so, to communicate with 

 the exterior through the mediation of a shallow sac opening 

 by a porus genitalis disposed immediately behind the anus. 

 Huxley has pointed out, among other things, that this pore can 

 have nothing to do with the pori abdominales of Ganoids and 

 Elasmobranchs ; and, were not his reasoning sufficient, the later 

 discovery by Max Weber * of the general co-existence of the two 

 in Salmonoids disposes of future misunderstanding on this 

 point. 



Balfour and Parker have shown (as Huxley points out f) 

 that the oviduct of Lepidosteus passes through an Osmeroid stage 

 in its development ; and the recent researches of Jungersen have 

 proved |, on appeal to embryology, that the oviduct of Osmerus 

 is, as Huxley supposed, homologous with that of all other bony 

 fishes and G-anoids. 



It is now known that whereas in the majority of Teleosfcei and 

 in Lepidosteus the ovary is a closed sac, lodging a central cavity 

 continuous with the lumen of its duct, in the Osmeroidei and 

 In the remaining Granoids the former is a folded plate and the 

 latter a more or less incomplete tube with a wide ostium ; while 

 in the Salmones, Muranidce, and Cohitis §, as in the Galaxiidce 

 NotojpteridcB, and Hyodon |i, the " oviduct " is either insignificant 

 or absent. 



Jungersen's researches place it beyond doubt that the genital 

 pores of those Teleostei devoid of genital ducts are one and the 

 same with the ostia of the latter when present. Eelying 

 upon his discovery that the genital glands are well differen- 

 tiated before traces of their ducts ever appear, he has concluded 

 {loc. cit. p. 183) that the ductless condition must have been the 

 more primitive one. Against this must be set : — i., the invariable 



* Morph. Jahrb. Bd. xii. p. 366 (1887). 



t Loc. cit. p. 136. 



X Loo. cit. pp. 181 & 192. 



§ Eathke, " Ueb. d. Darmkanal u. d. Zeugungsorgane d. Fische," Schrift. d. 

 iiaturf. Gesellsch. z. Dauzig, H. iii. Bd. 24 (1824). 



II Gf. Gllntber, 'Introd. to Study of Fishes,' p. 158; and Jimgerseu, loc. cit. 

 pp. 1 & 182-3. 



