Contrasting with this neat and pretty little family, we have here
another species of the genus, the Four-angled Squirter.[153] You would
hardly suppose this to be an animal at all, if uninitiated; but might
readily pass it over as a rude stone, or a bit of wood roughly bruised
and worn by the waves beating it among the rocks, so uncouth and coarse
and shapeless it is. It forms a great mass, some two inches high,
rudely four-sided, of a dull yellowish-olive hue, rising into two blunt
eminences, which individually retain the quadrangular shape, and in
activity open by symmetrically quadrangular orifices. It is a sluggish,
unattractive lump of flesh, somewhat between leather and jelly in
texture, coarsely pellucid, but not transparent, and its exterior is
usually distinguished by various extraneous matters imbedded in the
test, as well as by forests of tangled zoophytes which creep over it
and root in it as on the rock. The surface itself, moreover, is much
corrugated by an irregular network of depressions, marking off angular
warty areas.
On the other hand, the little Currant is a pleasing inhabitant of the
aquarium. Of manners, to be sure, it has not much, good or bad, but the
form and colour are agreeable; as is also the effect produced by the
grouping of the brilliant drops of jelly. Little of change takes place,
beyond the occasional contraction and reprotrusion of the orifices; but
sometimes you may see, as I have seen, at certain times, the laying of
eggs by this species, which is an interesting phenomenon. These are
perfectly globular, about the size of small shot or pins’ heads, of a
rich scarlet-crimson hue: they are deposited in a singular manner. The
oviduct does not extend to the exterior of the body, but discharges the
eggs into a large cavity formed by the mouth, of which the discharging
siphon is the outlet. From this orifice, then, they are expelled, shot
out perpendicularly with considerable force, so that they describe
arched courses through the water, like bombs shot from a mortar, rising
to a height ten times that of the animal. I have observed a dozen or
more eggs thus discharged in quick succession, which then fall to the
bottom around the parent, destined to constitute one of those family
groups in which we usually find the species.
I have not been successful in rearing these eggs to maturity. The
development of the _Tunicata_ has, however, been observed by various
naturalists, and by none more thoroughly than by the late Sir John
Dalyell, whose elaborate and costly works, profusely illustrated, are
such a mine of information respecting the lower forms of marine life.