JOURNAL OF MICROSCOPICAL SCIENCE. 



EXPLANATION OF PLATES XVII, XVIII & XIX. 



Illustrating Mr. Balfour's memoir on " Structure and De- 

 velopment of the Vertebrate Ovary." 



EXPLANATION OF PLATE XVII 



List of Reference Letters. 

 po. Primitive ovum. do. Permanent ovum in the act of being formed. 

 0. Permanent ovum. fe. Follicular epithelium, ov r. Ovarian portion 

 of ovarian ridge, ps e. Pseudo-epithelium of ovarian ridge, ep. Non- 

 ovarian epithelium of ovarian ridge, n n. Nests of nuclei of ovarian region. 

 sir. Stroma of ovarian ridge, v. sir. Vascular region of stroma adjoining 

 ovarian ridge. I. sir. Lymphatic region of stroma, v. Blood-vessel, dv. 

 Developing blood-vessels, .v. Modified nucleus. 



Fig. 1. — Transverse section of the ovarian ridge of an ev.ibryo of Sty. 

 canicidci, belonging to stage p, showing the ovarian region with thickened 

 epithelium and numerous primitive ova. Zeiss, c, ocul. 2. Ficric acid. 



Fig. 2. — Transverse section of the ovarian ridge of an embryo of 

 Scyllium catiicula, considerably older than stage Q. Zeiss, c, ocuL 2. Picric 

 acid. Several nests, some with distinct ova, and others with the ova fused 

 together, are present in the section {n. n.), and several examples of modified 

 nuclei in still distinct ova are also represented. One of these is marked .r. 

 The stroma of the ovarian ridge is exceptionally scanty. 



Fig. 3. — Transverse section through part of the ovarian ridge, including 

 the ovarian region of an almost ripe embryo of Scyllium canicula. Zeiss, c, 

 ocul. 2. Picric acid. Nuclear nests {n. n.), developing ova {d. o.), and ova 

 {o.), with completely formed follicular epithelium, are now present. The 

 ovarian region is still well separated from the subjacent stroma, and does 

 not appear to contain any cells except those of the original germinal epi- 

 thelium. 



Fig. 4. — Section through ovarian ridge of the same embryo as fig. 3, 

 to illustrate the relation of the stroma (sfr.) and ovarian region, Zeiss, a a, 

 ocul. 2. Picric acid. 



Fig. 5. — Section through the ovarian ridge of an embryo of Scyllium 

 canicula, 10 cm. long, in which the ovary was slightly less advanced than 

 in fig. 3. To illustrate the relation of the ovarian epithelium to the sul;- 

 jacent vascula stroma. Zeiss, a, ocul. 2. Osmic acid. y. points to a small 

 separated portion of the germinal epithelium. 



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. canicula. Zeiss, c, ocul. 2. 

 Picric acid. It shows the vascular ingrowths amongst the original epithelial 

 cells of the ovarian region. 



