DORIS PILOSA.
generally partaking, more or less, of the colour of the body: they are occasionally freckled with
brown. Head surrounded by a short veil, produced at the sides into broad, flat oral tentacles,
rounded at the ends, and a little angulated in front: they vary in shape according to the
degree of expansion, and have usually a leaf-like appearance. Foot oblong, rounded at both
ends, and extending a little beyond the cloak when the animal is crawling. It is of the same
colour as the body, though usually rather paler, and, from its transparency, shows the liver,
forming a brown patch near the centre. The spicula are rather small and nodulous, in this
respect resembling those of a Goniodoris, to which genus, in some of its characters, this
species approximates.
The Protean character of this common species makes it difficult to assign the limits of its
variation, and consequently several species have been constituted out of i t ; we are now, however,
inclined to consider all those we have given in our list of synonyms to be varieties of
the same. We were for some time unable to ascertain the species of Bomme on which the
Doris stellata of Gmelin was founded, having in vain attempted to find a copy of the work in
which it is described in the libraries of this country. Through the kindness of a friend,
however, we have been put in possession of a translation of Bomme’s papers, with tracings of
the plates. From these we are enabled to state, that his species is certainly our Doris pilosa.
The description and figures are excellent, making a little allowance in the latter for the period
when they were published. tc The back,” he says, “ is elevated in the form of an egg, and
rounded behind; the upper part of the body is as if covered with fu r,...........this covering
(cloak) is very rough, and clothed throughout with soft points.” The pointed nature of the
papillae is also represented in the figures. Gmelin has, notwithstanding, rendered the
character by these words, “ supra tuberculis obtusis aspersa:” and Cuvier and Lamarck have
each called the tubercles “ ro u n d ed th e former, perhaps, deceived by the contraction of
spirit specimens. We do not wonder, therefore, to find succeeding authors at a loss about this
Doris, or that Philippi should describe a species as Doris stellata, with the branchiae retractile
within a cavity. The branchial plumes of this species are contractile only, as is well described by
B o m m e “ The most beautiful part of this little animal is the flower-like star on the rump........
This star is very sensitive: at the slightest touch the animal draws it as firmly as possible
to g e th e r—words perfectly describing the action, as we have frequently observed it. There
is no branchial cavity in this species. The Doris pilosa of Müller is not quite so easily
recognised, the description and figures being much inferior to Bomme’s ; but as succeeding
authors have generally agreed in referring it to the species now under consideration, and the
description, as far as it goes, is sufficiently appropriate, we have thought it best to retain the
name. Professor Loven, however, considers our species to be the D. fusca of Müller, the
figure of which, in ‘ Zoologia Danica,’ he states to have been inserted by mistake. That the
D. fusca of Loven’s ‘ Index’ is the same as ours, we are enabled to state from the examination
of specimens obligingly sent to us by the author. Doris subitems of Thompson we refer to
this species, with some slight doubts. In this case, also, we have been kindly favoured with
an examination of the specimen described. In all its characters it agrees perfectly with
Doris pilosa, excepting that the cloak appears nearly smooth, a circumstance we are inclined
to attribute to its state of preservation; we have seen living examples of the large variety,
with the papillae less conspicuous than in others. As to our own Doris similis, the principal
peculiarity of which is the want of the white star in the branchiae, we think it safest at
DORIS PILOSA.
present to merge it also among the varieties of this difficult species, leaving it to time to show
if any permanent difference can be substantiated. Doris rocinela and D. ochracea, of Leach,
specimens of which are preserved in the British Museum, appear to be varieties of D. pilosa.
The breeding season of this species commences in April, but the spawn is not abundant
until May or June, and patches may occasionally be found as late as September; it is
of a pretty cup-like form, with the margin turned outwards, and in some cases a little
flounced. The ova, which are small and whitish, are very numerous, and arranged in distinct
transverse lines.
Doris pilosa inhabits the littoral and laminarian zones, and is often found further above
low-water mark than most of its congeners. It is comparatively active, and is with difficulty
kept alive in confinement, from its propensity to crawl out of the water. Its range, as far
as we at present know, is confined to the Atlantic shores of Europe.
The heart pulsates about sixty-eight times in a minute.
Figs. 1, 2, 3. Doris pilosa, different views.
4. A portion of the cloak, highly magnified.
5. Dorsal tentacles.
6. A branchial plume.
7. Spicula.
8. Anal nipple.
9. Spawn.
10. A portion of the same, showing the ova.