EXPLANATION OF PLATE 25. XXXvii 



trate the relation of the ovarian epithelium to the subjacent vascular stroma. Zeiss A, 

 ocul. 2. Osmic acid. y. points to a small separated portion of the germinal epithe- 

 lium. 



Fig. 6. Section through the ovarian ridge of an embryo of Scyllium canicula, 

 slightly older than fig. 5. To illustrate the relation of the ovarian epithelium to the 

 subjacent vascular stroma. Zeiss A, ocul. 2. Osmic acid. 



Fig. 7. More highly magnified portion of the same ovary as fig. 6. To illustrate 

 the same points. Zeiss C, ocul. 2 . Osmic acid. 



Fig. 8. Section through the ovarian region (close to one extremity, where it is 

 very small) from a young female of Scy. canicitla. Zeiss C, ocul. i. Picric acid. It 

 shews the vascular ingrowths amongst the original epithelial cells of the ovarian 

 region. 



Fig. 9. Section through the ovarian region of the same embryo as fig. 8, at its 

 point of maximum development. Zeiss A, ocul. 2. Picric acid. 



Fig. 10. Section through superficial part of the ovary of an embryo, shewing 

 the pseudo-epithelium ; the cells of which are provided with tails prolonged into the 

 general tissue of the ovary. At./, e. is seen a surface view of the follicular epithelium 

 of an ovum. Zeiss C, ocul. 2. Picric acid. 



Fig. ir. Section through part of an ovary of Scyllium canicula of stage Q, with 

 three primitive ova, the most superficial one containing a modified nucleus. 



Fig. 12. Section through part of an ovary of an example of Scyllium canicula, 

 8 cm. long. The section passes through a nest of ova with modified nuclei, in which 

 the outlines of the individual ova are quite distinct. Zeiss E, ocul. 2. Picric acid. 



Fig. 13. Section through part of ovary of the same embryo as in fig. 5. The 

 section passes through a nest of nuclei, with at the least two developing ova, and also 

 through one already formed permanent ovum. Zeiss E, ocul. 2. Osmic acid. 



Figs. 14, 15, 16, 17, 18 [Figs. 17 and 18 are on PL 25]. Sections through parts 

 of the ovary of the same embryo as fig. 3, with nests of nuclei and a permanent ova 

 in the act of formation. Fig. 14 is drawn with Zeiss D D, ocul. 2. Figs. 15, 16, 

 17, with Zeiss E, ocul. 2. Picric acid. 



PLATE 25. 



LIST OF REFERENCE LETTERS. 



do. Permanent ovum in the act of being formed.- dyk. Developing yolk, f ' e. 

 Follicular epithelium, fe'. Secondary follicular epithelium, g v. Germinal vesicle. 

 n n. Nests of nuclei of ovarian region, o. Permanent ovum. pse. Pseudo-epithelium. 

 sir. Stroma ingrowths into ovarian epithelium, vt. Vitelline membrane, x. Modified 

 nucleus, yk. Yolk (vitellus). z . Zona radiata. 



[Figs. 17 and 18. Vide description of Plate 24.] 



Fig. 19. Two nuclei from a nest which appear to be in the act of division. From 

 ovary of the same embryo as fig. 3. 



Fig. 20. Section through part of an ovary of the same embryo as fig. 6, contain- 

 ing a nest of nuclei. Zeiss F, ocul. 2. Osmic acid. 



