220 On some Disputed Points in Teleostean Embryology. 



that this tissue is not properly speaking an epithelium, but 

 a mass of cells of two kinds, namely genital cells distin- 

 guished by their large size and what he calls stroma-cells. 

 Jungersen represents the genital cells at all stages, although 

 they multiply by division, as uninucleate. 



M'Intosh and Prince have not included the later develop- 

 ment of the generative organs in their researches ; but they 

 give an account of the genital cells at the earliest stage which 

 is in striking contrast to any previously given. They state 

 that each of the primitive ova is " a more or less perfect 

 sphere and encloses numerous minute nucleated bodies." 

 They point out that these ova are quite unlike the primitive 

 ova of Elasmobranchs as described by Balfour, for these latter 

 are uninucleate. It is obvious that these authors have either 

 misunderstood the structure of the primitive ova which they 

 saw, or the multinucleate cells they describe were not primi- 

 tive ova at all, but something else. It is at all events certain 

 that the primitive ova of Teleosteans are, like the ova of most 

 other animals, large cells with a single large nucleus. 



List of References. 



(1) J. T. Cunningham. "The Significance of Kupffer's Vesicle, with 

 Remarks on other Questions of Vertebrate Morphology," Quart. 

 Journ. Micr. Sci. vol. xxv., 1885. 



(2) . " On the Relations of the Yolk to the Gastrula in Teleo- 

 steans and in other Vertebrate Types," ibid. vol. xxvi., 1885. 



(3) . " On the Structure and Development of the Reproductive 



Elements in Myxine glutinosa" ibid. vol. xxvii., 1886. 



(4) . " Studies of the Reproduction and Development of Teleo- 

 stean Fishes occurring in the Neighbourhood of Plymouth," Journ. 

 Mar. Biol. Assoc, no. 1, n. s., 1889. 



(5) . " The Eggs and Larvse of Teleosteans," Trans. Roy. Soc. 



Edinb. vol. xxxiii. pt. i., 1886. 



(6) Agassiz and Whitman. " On the Development of some Pelagic 



Fish-Eggs," Proc. Amer. Acad. Arts and Sci. vol. xx., 1884. 



(7) . " The Pelagic Stages of Young Fishes," Mem. Mus. Comp. 



Zool. Harvard Coll. vol. xiv., no. 1, pt. 1, 1885. 



(8) E. E. Prince. " On the Presence of Oleaginous Spheres in the 

 Yolk of Teleostean Ova," Ann. & Mag. Nat. Hist. ser. 5, vol. xviii. 



1886. 



(9) M'Intosh and Prince. " On the Development and Life-Histories 



of the Teleostean Food- and other Fishes," Trans. Roy, Soc. Edinb. 

 vol. xxxv. pt. iii., 1890. 



(10) W. C. M'Intosh. "On the Pelagic Fauna of the Bay of St. 

 Andrews during 1888," Annual Report of the Fishery Board for 

 Scotland. 1889. 



