. La cyclopaedia d'anatomie et physiologie. Anatomie ; physiologie ; Zoologie. [106] ovule. qui les subdiviser ; et comme ces plis sont formés les longitudinales qui beome allié diplômés moins profonde. La surface de l'œuf présente ensuite l'apparence réticulée qui est montré dans Fig. 70.* sur la création d'une section à travers un tel oeuf,^ trempée dans l'alcool ou tout autre réactif approprié, il est facile de par- cevoir une que le ovicapsule ne prend aucune part dans les inflexions, mais qu'elles se composent entièrement dans le rainurage de l'oeuf, et la flexion correspondante dans les rainures de la mem- brane vitelline. Ce

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. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. [106] OVUM. which subdivide them; and as these cross folds are formed the longitudinal ones beome gradu- ally shallower. The surface of the egg then presents the reticulated appearance which is shown in fig. 70.* On making a section through such an egg, hardened^ in alcohol or any other suitable reagent, it is easy to per- ceive that the ovicapsule takes no part in the inflections, but that they consist entirely in the grooving of the yolk, and the corresponding bending into the grooves of the vitelline mem- brane. This state is maintained till the ovum is approaching maturity, when the depth of the grooves or folds speedily diminishes; and these come at last to be completely effaced in those ova which have left the ovicapsule. In Loligo, it is stated by Kolliker, there are only the longitudinal folds. No satisfactory opinion has been offered as to the cause of this peculiar structure. Fig. 70 *.. Ova of the Sepia. (.From Kolliker.') A. Three ovarian ova of the Sepia in somewhat different stages of advancement attached by their pedicles to the ovary, and represented several times magnified. They all show the reticulated mark- ings on the surface produced by the folding in of the vitelline membrane ; g, the place of the germi- nal vesicle and possibly also of a micropyle at the small pole of the egg, in which segmentation after- wards occurs. B. Direct view of this germinal pole of one of the ova, showing the absence of the folds towards the centre in which the germinal vesicle is situated. c. Cross section of one of the ova, showing at o the unfolded or smooth ovarian capsule, and at v m the folded vitelline membrane. Towards the narrow pole of the ovum, the folds now described become less marked ; and they are entirely absent just at the pole itself, so that the germinal vesicle may be seen in the smooth space which is left between them. At this place I had some expectation to find an apertu

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