Page:Natural History, Mollusca.djvu/112

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100
NUDIBRANCHIATA.

therefore, to pass through a metamorphosis before it attains its permanent condition.

Natural History - Mollusca - Eolis larva.png

LARVA OF EOLIS.

The eggs in all the species are numerous. They are deposited, during the spring and summer, commonly in the form of a broad ribbon of clear jelly, attached by one of its edges to some solid substance, and generally coiled, or irregularly twisted, or frilled. The eggs themselves are arranged in close-set rows, crossing the gelatinous belt, and giving an opaque white appearance to the mass, which would otherwise be colourless.

In general each egg-shell (chorion) contains but a single yolk, but in some of the Dorides each contains two or three; and in the elegant Antiopa cristata, a specimen of which lately spawned in my possession, I found, upon the average, the extraordinary number of sixty yolks in each egg shortly after deposition. The yolk, which is contained within a delicate, transparent, membranous