Fam. 1, Plate 12.
Figs. 1 to 8.
DORIS DEPRESSA, Alder and Hancock.
D. valde depressa, subpellucida, spiculosa; pallio lutescenti, rufo-maculato, papillis gracilibus,
acuminatis, subremotis; tentaculis linearibus luteolis; branchiis 11, minutis, pinnatis, anum subremote
cingentibus.
Doris depressa, Aid. and Hanc. in Ann. Nat. Hist. v. 9, p. 32.
Hub. Under stones near low-water mark. Cullercoats and Whitley, Northumberland, A. H.
Scarborough; Torquay, J. A.
Body from a quarter to three eighths of an inch long, and about two thirds as broad;
thin, transparent, and very much depressed, of an elliptical or slightly ovate form, being
nearly equally rounded at both ends. Cloak of a dull yellowish or sandy colour, sometimes
inclining to rosy, and sprinkled with reddish, orange, or purple-brown spots, assuming an
indistinct linear arrangement on the top of the back. It is covered with soft, linear, pointed
papillae, not very thickly dispersed over the surface, nor readily distinguishable: it is also filled
and stiffened with large spicula, arranged symmetrically, in a transverse direction down the
middle of the back, and diagonally at the sides, inclining from the head backwards; from the
transparency of the skin, these spicula are very conspicuous, and give the cloak an icy or
crystalline appearance. The back has a slight purplish shade, from the liver appearing
through the cloak. Dorsal tentacles linear, slender, and tapering a little upwards; they are
yellowish, with about ten laminae. Branchial plumes ten or eleven, whitish, transparent, and
almost colourless; simply pinnate, very small and inconspicuous, arranged in a nearly complete
circle round the anus, and at a little distance from i t : the circle is slightly broken behind, by
the posterior plumes inclining inwards. The pinnae are five or six in number, on each side
the plumes. Head dilated into a semicircular veil. Foot broadish, truncated in front,
rounded and not produced beyond the cloak behind. It is transparent and nearly colourless,
but the liver, appearing through, forms a large, elongated, dark-brown patch in the centre.
This is the only Doris in which we have observed the eyes appearing through the skin
in adult age. The spicula are of the usual form in Doris; those on the sides are remarkably
large in proportion to the size of the animal, equalling in length nearly the transverse diameter
of the body.
Our little Doris, in general appearance, so nearly resembles the figure given by D’Orbigny
of his Villiersia scutiyera, in Guerin’s s Magazin de Zoologie,’ that at first sight it might be
pronounced to be the same species; but an examination in detail shows differences that forbid
our considering them identical. We have no hesitation, however, in stating our opinion, that