♦
TRIOPA CLAVIGER.
The skin is densely filled with spicula, which are of various forms ; generally forked or
tijradiate, occasionally straight, and a few cruciform or dagger-shaped. The latter are mostly
found in the branchiae, and those of the first description are most developed in the lateral
processes.
Dr. Johnston was the first to notice this handsome species as a native of Britain, and
it has since been found to be pretty generally diffused. It varies a little in appearance, which
has induced some naturalists to think that more than one species might be included in it. but
no good distinguishing Characters have yet been pointed out. The four branchial plumes
. described and figured by Muller, are so unlike the usual appearance of those organs in.the
Dorididee that it is fair to conclude they have been misunderstood. The specimens found
on the Northumberland coast are much smaller, and have the branchiae much less developed
than those from the south of England4, the appendages of the cloak, too, are more'clavate, and
the orange colour does riot extend so far down thejn. This form is probably thé T pulcher
of Johnston, which is stated to haye tubercular branchiae ; a mistake arising from the
difficulty of observing them, on account of their minuteness and transparency.
Pigs. 1, 2, 3. Triopa claviger, different views.
4, 5. Pront and side views of a tentacle.
6. One of the frontal appendages much magnified.
7. Spicula. •