The operculum-plug area and membranous structure of the eggs of XXXX .

@entity13857 @entity3733 @entity4653
Eggs of @entity13857 were prepared for @entity4653 ( @entity4653 ) by the @entity3733 freeze-cracking method. The egg-shell and oocyte were examined by @entity4653 . The egg has a chitinous shell which consists of more than 10 layers of dense lamellae. The shell is bordered by a limiting membrane. An operculum and a collar made of chitinous shell together form the opercular area. The operculum is an empty cavity. The chitinous fibers of the egg-shell in this area are diffuse and loose, with numerous micropores or spaces. The egg-shell in this area therefore appears to form a fine tubular network. The oocyte is an undifferentiated cell with a biconcave drum-like shape. The perivitelline space is conspicuous at both ends of the cell.
