and a half in length. It may be distinguished by the brilliant blue which is always more or less
present on the branchiae, sometimes only giving them a faint tinge, at others forming a
streak down the front of each papilla; and sometimes a very beautiful variety occurs with
the blue nearly covering their whole surface. The branchiae are variable in number and
liable to fall off. An entire clump is sometimes wanting.
This is a very active animal, and whilst gliding forward its tentacles are in continual
motion, bending gracefully in all directions. Both pairs appear to be endowed with great
sensibility, contracting themselves and suddenly shrinking backwards on coming in contact
with anything. Sometimes they will do this without apparent cause. The branchiae, too,
usually partake of this restless motion, and are capable of great extension and contraction
at the will of the animal. We have had several opportunities of noticing the carnivorous
propensities of this species, which is certainly not the least voracious of its tribe. After
having been for a day or two without food, they will even devour their own kind, the weaker
falling a sacrifice to the cravings of the stronger. Large individuals will content themselves
with plucking off each other’s papillae; but should a smaller specimen be within reach, it is
most mercilessly attacked, the more powerful animal laying hold of any part of the weaker
that may happen to be nearest. The tail, however, is generally first seized, and fierce and
determined is the onset. The devourer raises and shakes his papillae in the manner that the
porcupine shakes its quills when irritated, and then, laying back the dorsal tentacles and
curling up the oral ones, fixes the protruded mouth and jaws upon his prey, when, with a
convulsive shrinking up of the body, morsel after morsel is appropriated. In this manner
it is not uncommon to see an individual entirely devour another, half its own size. We have
also seen this species feed upon a I/ucernaria.
Eolis coronata spawns most abundantly in June, at which period it is rather plentiful
among the rocks at Whitby and Cullercoats ; patches of spawn, however, are not unfrequently
found in July, and occasionally in August. The spawn is attached to the underside of
stones, and is disposed in a close-set spiral coil of four volutions, consisting of a waved
gelatinous thread, with yellowish imbedded ova.
This species was first discovered by Professor E. Forbes in Shetland, and we have since
found it in several places; principally on the northern shores of our islands. On the
Northumberland coast it is one of the most common species, and in Malahide Bay we found
an orange variety of it in considerable numbers on large Laminaria and sponges dredged
in shallow water.
We suspect that the Eolis peregrina, mentioned by Dr. Grant as having been found in
the Frith of Forth, is this species, which somewhat resembles that of Cavolini in the colour
of the branchiae, but not in their arrangement. We see no good reason for believing that
the true E. peregrina has ever been found in this country.
The pulsations of the heart are about sixty-five in a minute.
Fig. 1, 3. Back and foot views of Eolis coronata.
2. Side view of the blue variety.
4. Two of the papillae more highly magnified.
5, 6. Dorsal tentacles.
7. Spawn.
8. A portion of the same more highly magnified.
9. Two teeth from the tongue highly magnified.