The genera _Ascidia_ and _Cynthia_ consist of isolated distinct
individuals; the _Clavelina_ and the _Perophora_ exist in the
form of groups, composed of distinct individuals associated by a
common branching root-thread, whence they irregularly bud forth.
There are, however, other genera, in which the compound life is
more prominently manifest, the individual being recognisable only
by carefully dissecting it out from the common mass. To this form
belong many gelatinous masses which occur on our rocky coasts; one
in particular,[154] conspicuous for its rich scarlet and orange
colours, which forms irregular pear-shaped lumps, that hang from
low-lying ledges, and that look not unlike strawberries. This is
extremely abundant. More attractive still are the _Botrylli_,[155]
which doubtless many persons have gazed on with admiration, wondering
what they can be,--animal, vegetable, or what. They look as if small
quantities of jelly had been spilt, sometimes on a stone, sometimes
on the broad leaf of a tangle, sometimes on a shrubby sea-weed,
entangling the twigs and leaves in the gelatinous mass. When we look
closely at such an object, we see that it is studded with little
starry systems of oblong specks, of some bright colour contrasting
with the ground-tint;--perhaps the stars are bright orange on a warm
brown, or pale straw-colour on a chocolate ground, or green on
an iron-grey. The stars vary in outline, often being angular, often
oval, or circular: they vary, too, in dimensions, and in number of the
constituent specks; some may be a sixth of an inch in diameter, and
contain a dozen or more; others may be less than half that size, and
have no more than two or three; or even a single speck may be seen here
and there, which has not yet begun to develop the starry form.
[Illustration: