Fam. 1, Plate 9.
FiyS. 1 to 9.
DORIS ASPERA, Alder and Hancock.
D. ovata, alba, pallio tuberculis validis, clavatis; branchiis 11 parvis, pinnatis, non retractilibus,
anum baud propinque cingentibus; capite velato.
Doris aspera, Aid. and Hanc., in Ann. Nat. Hist., v. 9, p. 32.
For. and Hanl., Brit. Moll., v. 3, p. 567.
Hab. Among the rocks between tide-marks; common on the Northumberland and Durham coasts.
Malahide, near Dublin; Ardrossan, Ayrshire, J. A. Burghead, Elgin, plentiful, Geo. Murray, Esq.
Body about four tenths of an inch in length, ovate, rather depressed, semi-transparent
white; rarely of a yellowish tinge. Cloak not extending much beyond the foot, covered with
rather , distant, stout, clavate, flattened tubercles, of nearly equal size, interspersed with a very
few smaller ones. The surface between the tubercles has an icy transparency from the spicula
shining through: the tubercles are more opaque. Dorsal tentacles rather long, nearly linear
or slightly tapering, a little bent backwards, with nine or ten rather distant laminae which
have usually a yellowjsh tinge; the basis of the tentacles are smooth and colourless: apertures
smooth, without sheaths. Branchial plumes eleven, small, simply pinnate, (with five or six
pinnae,) transparent white; the anterior ones longest, the posterior pair very short, often
scarcely shewing themselves above the tubercles. They are set at a little distance from the
anus, leaving a small area. Head with a semicircular veil, smooth at the margin. Foot rather
broad, rounded at the ends, and extending a little beyond the cloak behind, when the animal
is in progression. It is of a transparent white, sometimes a little yellowish, with a small, oblong,
reddish brown patch in the centre from the liver appearing through. There is likewise
a pinkish shade on the back of the animal from the same cause.
The spicula are very variable both in size and form. The larger ones are arranged across
the back, and diagonally at the sides, with a few of a slightly waved form running completely
round the cloak at a little distance from the margin. Small spicula are clustered into the
tubercles radiating at their base. Their usual shape is fusiform, obtusely pointed at the ends,
and a little bent in the centre, where there is generally a spur or branch, but many of the
smaller spicula, especially in the branchiae and the margin of the cloak, are crucial or daggershaped,
and this quadriradiate form is found, though less frequently, among the larger kinds.
From the crowding of spicula in the skin, and the large hard tubercles, the animal feels firm
and harsh to the touch.
This Doris appears to be rather local,*but is one of the commonest species on the north