1886.] MR. ROSSET ON THE FAUNA ETC. OF THE MALDIVES. 295 
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. 2.7. 
Zona radiata; its division into two layers is not shown. g.v. Germi- 
nal vesicle. (Zeiss A, Oc. 2.) 
Outline of attached ovum of Osmerus. s.m. The suspensory membrane 
formed by the zona radiata externa. 2.7.27. The zona radiata interna. 
(Zeiss A, Oc. 2.) 
. 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.7.2.. Zona radiata interna. z27.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.7.¢., 2.7.7., as 
before. (Zeiss E, Oc. 2.) 
i) 
id) 
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 :— 
“On my 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 Malé Atol. 
The principal object of my journey was to make a complete Ethno- 
graphical 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, &e. 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 Malé Atol, so that I was 
unable to visit the southern islands of the group. It will therefore 
