PLATE ILYlll—CoiUhiued. 



Fig. 25. — a. Ovum from the same ovary as fig. 21, containing in the 

 yolk three peculiar bodies, similar in appearance to the two small 

 bodies in the germinal vesicle. B. Germinal vesicle of a large ovum from 

 the same ovary, containing a body of a strikingly similar appearance to 

 those in the body of the ovum in a. Zeiss, e, ocul. 2. Picric acid. 



Fig. 26. — Section of the ovary of a young female of ScylUtm stellare 

 164 centimetres in length. The ovary is exceptional, on account of the 

 large size of the stroma ingrowths into the epithelium. Zeiss, c, ocul. 2. 

 Osmic acid. 



EXPLANATION OF PLATE XIX. 



List of Reference Letters for Figs. 27 — M. 



y"6?. Follicular epithelium, fe'. Secondary follicular epithelium, vt. 

 Vitelline membrane, z.n. Zona radiata. yk. Yolk (vitellus). ff.v. Ger- 

 minal vesicle. 



Fig. 27. — Ovum of Scyllium canicula, o. 5 mm, in diameter, treated with 

 osmic acid. The figure illustrates the development of the yolk and a pecu- 

 liar mode of proliferation of the germinal spots. Zeiss, a, ocul. 2. 



Fig. 28. — Small part of the follicular epithelium and t^^g membranes of 

 a somewhat larger ovum of Scyllium canicula than fig. 22. Zeiss. D p, 

 ocul. 2. 



Fig. 29. — The same parts as in fig. 2S, from a still larger ovum. 

 Zeiss, DD, ocul. 2. 



Fig. 30. — Ovum of Raja with follicular epithelium. Zeiss, c, ocul. 2. 



Fig. 31. — Small portion of a larger ovum of Raja than fig. 30. Zeiss, D d, 

 ocul. 2. 



Fig. 32. — Follicular epithelium, &c., from an ovum of Raja still larger 

 than fig. 31. Zeiss, D D, ocul. 2. 



Fig. 33. — Surface view of follicular epithelium from an ovum of Raja 

 of about the same age as fig. 33. 



Fig. 34. — Vertical section through the superficial part of an ovary of 

 an adult Raja to show the relation of the pseud-epithelium to the sub- 

 jacent stroma. Zeiss, dd, ocul. 2. 



Complete List of Reference Letters for Mammalian Ovary. 



oi\ Ovary, g e. Germinal epithelium, t. Tubuliferous tissue, derived 

 from Malpighian bodies, p o. Primitive ovum. 7i. Nest of cells of the 

 germinal epithelium. 7i d. Nuclei in the act of dividing, do. Deve- 

 loping ovum. 0. Permanent ovum. fe. Follicular epithelium, fc. Cells 

 which will form the follicular epithelium, mg. Malpighian body. 



Fig. 35. — Transverse section through the ovary of an embryo rabbit 

 of eighteen days, hardened in osmic acid. The colours employed are 

 intended to render clear the distinction between the germinal epithelium 

 {ff e.) and the tubuliferous tissue (L), which has grown in from the Wolfiian 

 body, and which gives rise in the male to parts of the tubuli seminiferi. 

 Zeiss, A, ocul. 2. 



Fig. 35 a. — Transverse section through a small part of the ovary of an 

 embryo from the same female at fig. 35, hardened in picric acid, showing 

 the relation of the germinal epithelium to the subjacent tissue. Zeiss, d d, 

 ocul. 2. 



