384 f. m. bai.foir. 



Summary of Observations on the Deyelopmknt of the Ovaby in 



SCYLLIUM AND IN KaJA, p. 415. 



Development of Mammalian Ovary, p. 118 — 433. 

 Literature, p. 418. Development of Ovary and Ova, p. 419. 



Summary of Observations on the Development of the Ovary 

 IN Mammalia, p. 431. 



General Observations on the Structure and Development of 

 the Ovary in VERTi:.BRATA, p. 433. 



The present paper records observations on the ovaries ^^Jm^ 

 two types, viz., Mammalia and Elasmobranchii. The main }Toints 

 dealt with are three: — 1. The relation of the germinal epithelium 

 to the stroma. 2. The connection between primitive ova in 

 Waldeyer^s sense and the permanent ova. 3. The homologies 

 of the egg membranes. 



The second of these points seems to call for special attention 

 after Semper's discovery that the primitive ova ought really to 

 be regarded as prijmtire semial cells, m that they give rise to the 

 generative elements of both sexes. 



The Development of the Elasmobranch Ovary. 



The development of the Elasmobranch ovary has recently 

 formed the subject of three investigations. The earliest of them, 

 by II. Ludwig, is contained in his important work, on the 

 ' Formation ot the Ovum in the Animal Kingdom." ^ Ludwig 

 arrives at the conclusion that tlie ovum and the follicular epithe- 

 lium are both derived from the germinal epithelium, and enters 

 into some detail as to their formation. Schultz," without appa- 

 rently being acquainted with Ludwig's observations, has come to 

 very similar results for Torpedo. 



Semper,^ in his elaborate memoir on the urogenital system of 

 "Rlasmobranchs, has added very greatly to our knowledge on this 

 subject. In a general way he confirms Ludwig's statements, 

 though he shows that the formation of the ova is somewhat more 

 complicated than Ludwig had imagined. He more especially 

 lays stress on the existence of nests of ova (Ureierernester), derived 

 from the division of a single primitive ovum, and of certain 

 peculiarly modiiied nuclei, which he compares to spimlle nuclei 

 in the act of division. 



My own results agree with those of previous investigators, 

 in attributing to the germinal epithelium the origin both of the 

 follicular epithelium and ova, but include a number of points 



' Arbcitcn, ii. d. 'Zool. Zoot. Institut. VVuizliiug,' BJ, i. 



'^ ' Arcliiv f. niikr. Aiiat.,' vol. xi. 



^ Arbeiten, a. d. 'Zool. Zoot. Iiibtilut. Wiirzbiirf:,' Bd. ii. 



