TRIOPA CLAVIGER.
The skin is densely filled with spicula, which are of various forms ; generally forked or
triradiate, 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 he pretty generally diffused. It varies a little in appearance, which
has induced some'naturalists to think that more than one species might be included m it, but
no good distinguishing characters have yet been pointed out. The four branchial plumes
described and figured by Midler, are so unlike the usual appearance of those organs in the
Dorididm that it is fair to conclude they have been misunderstood. The specimens found
on the Northumberland coast are much smaller, and have the branchim much less developed
than those from the south of England; the appendages of the cloak, too, are more clavate, and
the'orange colour does not extend so far down them. This form is probably the T. pulcher
of Johnston, which is stated to have tubercular b?anchfe; 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..