Fam. 1, Plate 24.
POLYCERA LESSONII, D’Orbigny.
P. virescens, vel luteola, corrugata, tuberculis luteis: tentaculis sub-clavatis, obtusis, 12-13
laminatis : velo parvo, multi-lobato : appendicibus branchiarum. 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. Scandi p. 6.
Doris illuminata, Gould, Invert. Massach. p. 4 (?).
Sab. 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,rf-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, rather short, stout, and much rounded in the laminated p a rt: laminte 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 bright lemon yellow:
behind these is a central tuberculated ridge extending to the tail. Branchiee composed of
three rather small, doubly pinnate plumes, of the same colour as the body, hut 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-brhwn
from the liver appearing through the centre; the whole surface minutely freckled with darkish
green. I ti s squared, transversely slit, and a little produced laterally in front, behind which
the sides are parallel, tapering posteriorly to a hluntish 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 deepwater on the Northumberland
coast, inhabiting the region of Corallines, and almost exclusively found on Germllaria
loriculata, which appears to he its favorite food. This zoophyte is brought in abundantly by
the fishermen at Cullercoats adhering to their lines, and, by examining it carefully, individuals