358 
PROFESSOR ARTHUR ROBINSON ON 
ovarian cumulus, and the separation of the cumulus cells into an outer group which will be dispersed, 
and an inner group which will form the corona radiata. The reticular character of the primary liquor 
folliculi is also shown, x 65. (Specimen P.D. C/16. 31 hours after insemination.) I.H. O.G. 
Fig. 16. The ovarian cumulus and part of the wall of the follicle shown in fig. 15. x 310. Showing 
more definitely the separation of the cumulus cells into two groups, and the relationship of the. reticulum of 
the primary liquor folliculi to the follicular cells and to the cells of the cumulus. 
Fig. 17. Section through an ovarian follicle of a ferret 27£ hours after insemination, showing the 
commencing dispersion of the more external cumulus cells. x 55. The membrana interna is quite distinct 
on the inner surface of the follicular epithelium and on the outer surface of the cumulus. (Specimen F.G.A. 
1/15. R.Z. 271 hours.) I.H. 
Fig. 18. Section through an ovarian follicle of a ferret 19f hours after insemination, x 30. The 
ovum is in the first maturation spindle stage, hut the section does not pass through the spindle. The 
membrana interna surrounds the primary liquor folliculi. . The secondary liquor folliculi is dispersing the 
outer cells of the ovarian cumulus, and is also beginning to force its way between the membrana interna and 
the inner surface of the follicular epithelium. (Specimen F. 3-5. Z. 1904.) H-.E. 
Fig. 19. Section through the ovarian follicle of a ferret 30| hours after insemination. x 30. Part of 
the primary liquor folliculi has been coagulated and shrunk by the fixing fluid. The membrana interna has 
been separated from the follicular epithelium to a greater extent than in the specimen shown in fig. 18, and 
part of it has been dragged into folds by the contraction of the coagulated primary liquor folliculi. 
(Specimen F.D. D/16. L.P.N.F. 301 hours.) I.H. O.G. 
Fig. 20. Section through an ovarian follicle of a ferret 26| hours after insemination. x 30. The 
ovum was in the first polar body stage, but the polar body and the second spindle are not in the plane of the 
section. Although the amount of secondary liquor folliculi in the region of the cumulus is not greater than 
in the follicle shown in fig. 19, the membrana interna is separated from the follicular epithelium to a greater 
extent — that is, along the whole of one side and at the superficial part of the follicle. (Specimen F.D.A. 
43/15. L.F1. 26| hours.) E. 
Plate IV. 
Fig. 21. Section through an ovarian follicle of a ferret 24 hours after insemination. x 30. The ovum 
was in the first polar body stage, and the polar body is seen as a black dot in the upper and left part of the 
ovum, close to the oolemma. The dispersion of the cumulus epithelium has proceeded to a greater extent 
than in the specimens shown in the previous figures ; there is also a greater amount of secondary liquor 
folliculi, and a greater extent of separation of the membrana interna from the follicular epithelium. (Specimen 
F.D.A. 39/15. R.Z. 24 hours.) I.H. 
Fig. 22. Section through an ovarian follicle of a ferret 19f hours after insemination. x 30. In this 
follicle the ovum was situated near the surface of the ovary, and was in the first maturation spindle stage, 
but the section does not pass through the plane of the spindle. There is greater dispersion of the cumulus 
epithelium than in the follicles shown in the preceding figures, and the membrana interna is separated from 
the follicular epithelium over more than a third of the superficial part of the wall of the follicle. (Specimen 
F. 3-5. Z. 1904. 19f hours.) H.E. 
Fig. 23. Section through an ovarian follicle of a ferret 21 hours after insemination, x 30. The 
ovum was in the first maturation spindle stage, but the section does not pass through the plane of the 
spindle. The follicle is of smaller size than those shown in the preceding figures, and the dispersion of the 
cumulus epithelium is less advanced than in the follicle depicted in fig. 22, but the separation of the 
membrana interna from the follicular epithelium is more advanced. (Specimen F.D.A. 41/15. R.F1. 
21 hours.) I.H. 
Fig. 24. Section through an ovarian follicle of a ferret 26^ hours after insemination. x 30. The 
ovum was in the first polar body stage, hut the section does not pass through the plane of the polar body. 
In the plane through which the section passes the membrana interna has been completely separated 
from the follicular epithelium by the secondary liquor folliculi. (Specimen F.D.A. 43/15. R.M. 
26£ hours.) I.H. 
Fig. 25. Section through an ovarian follicle of a ferret 41 hours after insemination, x 30. The 
