Page:Proceedings of the Royal Society of London Vol 60.djvu/504

470 Fig. 4— Another egg of 2V. maeromphalus,seen from above, with the longitudinal slit in the tipper wall of the outer capsule widened out so as to expose the inner capsule to view. d s

F ig. 5. Inner capsule of another egg to show the dorsal ridge along the dorsal suture (d. -v.) with its anterior terminal prolongation, and the lateral suture (l. s.). o. c., remains of outer capsule.

ruptured along the sutures. In the middle line of the lower surface of th e inner capsule there is a slight longitudinal groove, and other unim portant grooves often occur. W here the outer capsule is united to the inner capsule there is usually a depression or flattening in the wall of the latter.

The vitellus (fig. 6) does not fill th e entire cavity of the inner capsule, b u t is. surmounted by a layer of colourless, somewhat cloudy, viscid albumen which is massed up, as it were, at the two extremities of the egg. The yolk is of a rich brown colour, of very fluid con sistency, and sub-translucent. The surface of the vitellus is quite smooth. The length of the inner capsule is about 26 mm., while th at of the enclosed vitellus is 17 mm.

I am not in a position to say much about the embryonic area at present, but I have observed an area pellucida about the middle of