OVARIAN FOLLICLES IN FERRETS AND FERRET-POLECAT HYBRIDS. 357 
Plate I. 
Fig. 1. Surface view of the ovarian capsule and the cranial end of the uterine cornu of a ferret, 
x 1'8. A needle is placed in the opening through which the cavity of the capsule communicates with 
the peritoneal cavity. The corresponding aperture is seen in section in fig. 2, together with an ovum which 
has just escaped through the aperture into the peritoneal cavity. 
Fig. 2. Section of the ovary, ovarian capsule, and the cranial end of the uterine cornu of a ferret- 
polecat hybrid, x II. The section traverses the opening through which the interior of the ovarian 
capsule communicates with the peritoneal cavity, and a recently extruded ovum is seen escaping into the 
peritoneal cavity between the uterine cornu and the apex of one of the fimbriae of the cranial end of 
the oviduct. (Specimen P.D. C/16. L.Per. 31 J hours after insemination.) I.H. O.G. 
Fig. 3. Section through the cortex of the ovary of a ferret, showing ovarian follicles of various sizes, 
some normal and some degenerate. Some of the follicles are situated superficially and others deeply in 
the cortex. x 65. (Specimen F.D. T/16. L.M.F. 123^ hours after insemination.) I.H. O.G. 
Fig. 4. Section of several primitive ovarian follicles of a ferret. x 800. (Specimen F.G.A. 18/15. 
L.Mx. 32 days’ oestrus.) I.H. 
Fig. 5. Section of young ovarian follicles of a ferret, x 540. One of the follicles shows a surface 
view of the follicular epithelium. The other follicle has been cut obliquely, so that on one side a single 
layer of cubical epithelium is seen, and on the other side an oblique section through the cubical follicular 
cells is shown. (Specimen F.D. G/16. L.Per. 41£ hours after insemination.) I.H, O.G. 
Fig. 6. Longitudinal section through an ovarian follicle of a ferret, showing the ovoid form of the 
follicle, x 800. The follicular epithelium is entering on the two-layered stage at one end of the 
follicle. (Specimen F.D. A. 42/15. R. 28 days post-partum and not in heat.) 
Fig. 7. Section through an ovarian follicle of a ferret-polecat hybrid. x 540. The follicular 
epithelium is in the early part of the two-layered stage. (Specimen P.D. C/16. R.M.F. 31^ hours 
after insemination.) I.H. O.G. 
Plate II. 
Fig. 8. Longitudinal section of an ovarian follicle of a ferret, x 350. Follicle and ovum are both 
ovoid. The follicular epithelium is in the early part of the three-layered stage. (Specimen F.Z.R.A. 10/15, 
ancestrus period.) I.H. 
Fig. 9. Longitudinal section through an ovarian follicle of a ferret, showing the more rapid increase 
of the follicular cells at the poles of the follicle, x 540. (Specimen F.D. F/16. L.Mx. 40f hours after 
insemination.) I.H. 
Fig. 10. Oblique section through an ovarian follicle of a ferret, showing the commencement of the 
cavity (antrum folliculi) of the follicle at one pole of the follicle. x 540. (Specimen F.D. G/16. R.M.F. 
41 £ hours after insemination.) I.H. O.G. 
Fig. 11. Longitudinal section through an ovarian follicle of a ferret, showing a more advanced stage 
in the formation of the cavity of the follicle. x 540. (Specimen F.D. G/16. R.M.F. 41£ hours after 
insemination.) I.H. O.G. 
Fig. 12. Section through an ovarian follicle of a ferret, showing changes in the follicle cells as the 
cavity of the follicle increases. x 549. (Specimen F.D. G/16. L.Per. 41^ hours after insemination.) 
I.H. O.G. 
Fig. 13. Section through a part of a full-grown ovarian follicle of a ferret which was not inseminated 
though insemination was attempted, showing the strands of primary stroma which permeate the primary 
liquor folliculi and which are connected with the follicular epithelium. x 65. (Specimen F.Z.R. 1/14. 
6d.) I.H. 
Plate III. 
Fig. 14. Section through part of the ovarian follicle depicted in fig. 13. x 310. Showing the relation 
of the strands of the stroma of the primary liquor folliculi to the follicular epithelium and to the epithelium 
of ovarian cumulus. 
Fig. 15. Section of an ovarian follicle of a ferret almost ready for ripening, showing the stalk of the 
