PO LY CERA tE S S Q j j l l -
Fam. 1, Plate 24.
POLYCERA LESSONII, D’Orbigny.
P. virescens, vcl luteola, corrugata, tuberculis luteis: tentaculis sub-clavatis, obtusis, 12-13
laminatis : velo parvo, multi-lobato : appendicibus brauchiarum tubercularibus, sub ramosis luteis.
Polycera Lessonii, D’Orb., in Mag. de Zool. v. 7, p. 5, pi. 105. .
Polycera citrina, Alder, in Ann. Nat. Hist. v. 6, p. 340, pi. 9, f. 7-9 (young).
Polycera modesta, Loven, Index Moll. Scand. p. 6.
Doris illuminata, Gould, Invert. Massach. p. 4 (?).
llab. Common on corallines from ten to twenty fathoms water, and rarely at low-water mark,
Cullercoats. Dublin Bay, sparingly, J. A.
Body about half an inch, and occasionally three quarters of an inch long, ovate oblong,
a little contracted behind the head, swelling in the centre, and tapering to a point posteriorly;
of a yellowish-green colour, when adult,—pale lemon yellow in its younger state,:—covered
with blunt yellow tubercles of different sizes, generally arranged in indistinct lines. The,
skin is strongly wrinkled, and when examined with a magnifier the greenish colour is seen to
be chiefly communicated by a sprinkling of dark green dots on a yellowish ground. Dorsal
tentacles clavate, father short, stout, and much rounded in the laminated part: laminae twelve
or thirteen, close and compact. Eyes very minute, scarcely visible in- old individuals. Veil
margined with numerous tubercular points, interrupted in front, and expanded along the sides
of the head, forming an arch round the tentacles, behind which a line of tubercles is continued
along each side of the back to the branchiae, where it is again expanded and produced
into a cluster of from two to five obtuse, ovate branchial lobes, of a briglft lemon yellow:
behind these is a central tuberculated ridge extending to the tail. Branchiae composed of
three father small, doubly pinnate plumes, of the same colour as the body; But paler; From
the base of the two lateral Ones large branches spring, which might perhaps be considered as
two additional plumes. Head transversely elliptical, with the sides fleshy, and produced into .
obtuse points. Foot pale yellowish-green, with a darker border, and a patch of reddish-hrown
from the liver appearing through the centre; the whole surface minutely freckled with darkish
green. It is squared, transversely slit, and a little produced laterally in front, behind which •
the sides are parallel, tapering posteriorly to a bluntish point.
The spicula are similar to those of P. ocellata, but rather stouter in proportion to their ,
length. The heart beats sixty-two times in a minute.
This, is one of the commonest Nudibranchs from deep water on the Northumberland
coast, inhabiting the region of Corallines, and .almost exclusively found on Gemellaria y
loriculata, which appears to be its favorite food. This zoophyte is brought in abundantly by
the fishermen at Cullercoats adhering to their lines, and, by examining it carefully, individuals