vitelline membrane

noun

vitelline membrane

/ vɪˈtɛlɪn, -aɪn /

zoology a membrane that surrounds a fertilized ovum and prevents the entry of other spermatozoa

First recorded in 1835–45

Surrounding the embryo is a vitelline membrane, an inner, and an outer envelope (Fig. 1).

The zona is the first to disappear, and the vitelline membrane next becomes gradually thinner.

Both the vitelline membrane and the zona radiata are found in Raja, but in a much less developed condition than in Scyllium.

The stage of about the greatest development of both the vitelline membrane and zona radiata is represented on Pl.

The big cells have now become flask-shaped like those in Scyllium, and send a process down to the vitelline membrane.

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