A Hancock àd.mLitkoTÎHt hyA.Holm.es.
DORIS PLANATA.
DORIS PLANATA, Alder and Hancock
D. valde depressa, elliptica: pallio amplo, luteo-, fusco-, et rufescente-liturato, tuberculis
insequalibus, crebris: tentaculis dorsalibus subclavatis: tentaculis labialibus linearibus: brancbiis 7,
parvis, discoloribus, intra foramen retractilibus.
Doris planata, Aid. and Hanc. in Ann. Nat. Hist. v. 18, p. 292.
Hab. Dredged in Lamlasb Bay, Isle of Arran. J. A.-
Body nearly an inch long, elliptical, very much depressed. Cloak large and flat, thin
at the edges, and extending much beyond the foot; thickly covered with obtuse, warty
tubercles, mostly small but of very unequal sizes, the largest ones being arranged at
irregular intervals on each side of the back. The prevailing colour is reddish brown,
interspersed with dull lemon-yellow and purplish brown; the whole sprinkled with minute
dark brown spots. The tubercles in many places, especially near the centre of the back,
are tipped with opake white. Along each side of the back there are a few irregular
patches of dull yellow, marking the position of the larger tubercles, and between them the
back has a darker shade of purplish brown. The under side of the cloak is of a dull lemon-
yellow, sprinkled with a few small reddish brown spots; it is smooth, and marked with a
delicate veining of anastomosing lines, producing a shagreened appearance. Dorsal tentacles
stout, subclavate, yellowish; the laminae about twelve or thirteen in number, marked with
dark brown lines and blotches, and sprinkled with yellowish white; the lower part speckled
with purple-brown. The tentacles are placed rather near together, and are without sheaths,
the margins of the cavities being only a little, produced and tuberculated. Branchiee very
small, retractile within a large cavity. They consist of seven imperfectly tripinnate plumes,
rather pointed at the top, and of a very pale fawn colour, strongly blotched with opake
yellowish white and dark brown, giving them a pied appearance. Head very indistinct and
.scarcely visible, except when the mouth is protruded. Oral tentacles long, linear, rounded
at the ends, and usually held in a slightly curved position. Foot rounded in front, much
narrower than the cloak, and ending posteriorly in an obtuse point, which is seldom extended
beyond the cloak. It is of a deep lemon-yellow, fading into a brownish tint towards the centre,
where the liver appears through in a reddish brown patch. The front is deeply grooved
transversely—the groove extending more round the sides than usual— and the upper lamina
is notched in the centre.
One of the chief peculiarities of this interesting Doris, compared with others of the
same division, is its flatness, which gives it a good deal the appearance of a large Planaria.
Planaria-like, too, it changes its form with great facility, sometimes drawing itself up when
at rest into a nearly circular disc. The edges of the cloak are usually held in an undulated
position.