jelly.

_Molluscs._--Among the Mollusca, Crustacea and Insecta yolk-stored eggs
of very remarkable forms are commonly produced.

In variety, in this connexion, the Mollusca must perhaps be given the
first place. This diversity, indeed, is strikingly illustrated by the
eggs of the Cephalopoda. In the squids (_Loligo_), for example, the eggs
are enclosed in long cylindrical cases, of which there are several
hundreds, attached by one end to a common centre; the whole series
looking strangely like a rough mop-head. Each case, in such a cluster,
contains about 250 eggs, or about 40,000 in all. By way of contrast the
eggs of the true cuttle-fish (_Sepia_) are deposited separately, each
enclosed in a tough, black, pear-shaped capsule which is fastened by a
stalk to fronds of sea-weed or other object. They appear to be extruded
at short intervals, till the full complement is laid, the whole forming
a cluster looking like a bunch of grapes. The octopus differs yet again
in this matter, its eggs being very small, berry-like, and attached to a
stalk which runs through the centre of the mass.

The eggs of the univalve Mollusca are hardly less varied in the shapes
they take. In the common British _Purpura lapillus_ they resemble
delicate pink grains of rice set on stalks; in _Busycon_ they are
disk-shaped, and attached to a band nearly 3 ft. long. The eggs of the
shell-bearing slugs (_Testacella_) are large, and have the outer coat so
elastic that if dropped on a stone floor they will rebound several
inches; while some of the snails (_Bulimus_) lay eggs having a white
calcareous and slightly iridescent shell, in size and shape closely
resembling the egg of the pigeon. Some are even larger than the egg of
the wood-pigeon. The beautiful violet-snail (_Ianthina_)--a marine
species--carries its eggs on the under side of a gelatinous raft. No
less remarkable are the eggs of the whelk; since, like those of the
squids, they are not laid separately but enveloped in capsules, and
these to the number of many hundreds form the large, ball-like masses so
commonly met with on the seashore. When the eggs in these capsules
hatch, the crowd of embryos proceed to establish an internecine warfare,
devouring one another till only the strongest survives!

With the Mollusca, as with other groups of animals, where the eggs are
exposed to great risks they are small, produced in great numbers, and
give rise to larvae. This is well illustrated by the