Disputed Points in Teleostean Embryology. 219 



teristic of the post-larval sole." This seems to me a disin- 

 genuous style of criticism, unless, indeed, Prof. M'Intosh 

 really believes that the larval sole has different colours in 

 different places. The latter alternative is improbable ; and 

 if my reviewer thinks it more polite to suggest indirectly that 

 I have blundered than candidly to express a doubt of the 

 accuracy of my observation, I can only say that I do not 

 agree with him. However, the discrepancy between our 

 descriptions of the colour is easily explained. The yellow 

 chromatophores of the larval sole do appear stone-grey, and 

 often quite a silvery grey, when seen by reflected light either 

 with the unaided eye or with the microscope ; but when seen 

 by transmitted light under the microscope they are yellow. 

 The difference between these scattered larval chromatophores 

 and those of the adult is merely due to the smaller quantity 

 of the pigment and the absence of the opaque iridocytes from 

 the skin in the larva. As to the post-larval sole referred to 

 by Prof. M'Intosh and figured in the Scottish Fishery Board 

 Report, 1889 (10), I cannot without further evidence accept 

 the identification. It is not strictly speaking post-larval ; all 

 stages up to the commencement of the metamorphosis, that is 

 all symmetrical stages, should be called larval. I have seen 

 larvae of the sole of a corresponding stage, as well as in subse- 

 quent stages, and in all the anterior margin of the head is 

 much blunter and the mouth much more ventral than in Prof. 

 M'lntosh's figure. 



Development of the Generative Organs. 



Hector F. E. Jungersen, in a masterly paper, has recently 

 given a very complete and interesting account of the deve- 

 lopment of the ovaries and testes in Teleosteans. He has 

 shown that in the Physoclist forms which he investigated 

 the cavity of the ovary originates somewhat as McLeod 

 described in Belone, namely by the formation of a groove 

 on the surface of the genital ridge and the subsequent 

 closing of this groove to form a canal. He has also shown 

 that in the Physostomous forms, namely Cyprinoids, the cavity 

 of the closed ovary is formed in the same way as that observed 

 by me in Clupea sprattus, that is, not by the formation of a 

 groove in the genital ridge, but by the coalescence of the 

 lower edge of the genital ridge with another thinner ridge 

 which projects from the peritoneum on the outer or lateral 

 side of the genital ridge. Jungersen describes the genital 

 cells as appearing in the mesoblastic tissue at the dorsal side 

 of the body-cavity on either side of the mesentery. He shows 



15* 



