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Show 1886.] MR. ROSSET ON THE FAUNA ETC. OF THE MALDIVES. 29o two layers, the external of which has pores, which are larger and less numerous than those of the inner layer. The egg adheres by the surface of the external layer, but no separation of the two layers takes place. In Osmerus eperlanus the same differentiation occurs, and the external layer, after becoming attached by one point or other, detaches itself from the inner layer except at one circular area, thus forming a membrane by which the ovum is suspended from its attachment. It remains to be mentioned that in the unripe ova, which are forcibly expressed from the parent, there is a delicate structureless membrane external to the zona radiata. This is doubtless derived from the ovary ; it is perhaps the connective-tissue layer of the follicle, which becomes reduced in thickness as the egg attains its mature size ; it is certain that the perfectly ripe ovum is enveloped only in its double zona radiata. EXPLANATION OF PLATE XXX. Fig. 1. Nearly ripe ovum of Osmerus eperlanus, taken from female, and examined in fresh condition, a. Thin membrane derived from the ovary, not present in the naturally deposited mature ovum. z.r. Zona radiata; its division into two layers is not shown, g.v. Germinal vesicle. (Zeiss A, Oc. 2.) 2. Outline of attached ovum of Osmerus. s.m. The suspensory membrane formed by the zona radiata externa, z.r.i. The zona radiata interna. (Zeiss A, Oc. 2.) 3. The membranes of an almost mature ovum of Osmerus, as seen in the fresh state after rupture of the zona radiata externa by pressure of the cover-glass, z.r.i. Zona radiata • interna, z.r.e. Zona radiata externa. (Zeiss A, Oc. 2.) 4. The zona radiata of egg of Osmerus, as seen in fresh condition in optical section, in process of separation of the two layers, z.r.e., z.r.i., as before. (Zeiss E, Oc. 2.) May 18, 1886. Prof. W . H. Flower, LL.D., F.R.S., President, in the Chair. Mr. C. W . Rosset exhibited and made remarks on a series of photographs taken during a recent visit to the Maldive Islands, and gave the following account of his collections in these islands :- " O n m y return from an eighteen months' stay among the Veddas of Ceylon, I undertook a journey to the Maldives, in October 1885, in the course of which I passed seventy-five days on the Male Atol. The principal object of m y journey was to make a complete Ethnographical collection, as also to take a series of photographs of the people, objects and places of interest, and so on, and obtain full particulars about habits and customs, manufactures, trade, &c. I was also able to make a zoological collection. " I was not able to carry out my original plan, as the Sultan absolutely refused to allow me to quit Male Atol, so that I was unable to visit the southern islands of the group. It will therefore |