dogmatize about the specific distinctions of rare animals, of which no adequate figures
have been published,11 do not think we have any propf that there is more than one large
species of Lomcinotus, somewhat variable in the size of the radula and in coloration. The
whole range of colour variation seems to me less than is known to exist in many Chromo-
dorids, and Mr. Farran admits that the white forms, which superficially look different
from the others, are merely varieties. In a specimen from Ballynakill which he has
kindly sent me as representing in his opinion the true L. genei I can find no white
spots, though it is possible they may have been present in the living animal. The
facies of this specimen is exactly that of Hancock’s largest figure (pi. Ill, fig. 1), called
by him L. portlandicus, except that the reddish-brown colour is deeper and more
uniform.
The small species are L. mai'moratus and L. fiavidus, both British. With regard to
these the main question is, have they assumed their adult and final form, or are they
immature? Trinchese states that the young of L. eisigii differs markedly from the adult;
and if we recognize the possibility of modifications occurring during growth, it may be
said that the two small species present no characters either externally or in the buccal
parts which are incompatible with the idea that they are the young of L. genei. On the
other hand, if they are mature (on which point the evidence is inconclusive), the differences
in size and colour are, no doubt, sufficient specific characters. A further question is
whether L. marmoratus and L. fiavidus are distinct forms. If they are adults, they must
certainly be regarded as separate species. But if they are immature, then considering
that L. fiavidus is smaller than L. marmoraius, and that Trinchese states that the young
L. eisigii is geolidiform, it is probable that L. fiavidus is the youngest stage of the same
species. Alder and Hancock note the seolidiform characters of the type specimen. 1'
have examined at Plymouth a small living individual 4 mm. long and 1 mm. broad which
resembled their plate in coloration and external appearance. In the buccal parts and
general structure it agreed with L. marmoraius, except that the short thick papillse,
which were only twelve in number, showed no sign of a bulb.
As mentioned below, Alder and Hancock’s published plates of L. marmoratus are
wrong in representing the dorsal margin as continuous with the oral veil.
I recognize provisionally three species:
1. L. genei Verany.
= L. portlandicus Thomps.
L. ha/ncocki Norman.
L. eisigii Trinchese.
2. L. marmoratus A. & H.
3. L. fiavidus A. & H.
I t is possible that both of these latter will prove to be young forms of the first, but I
1 I have not seen a coloured drawing of the Mediterranean form, which must be the true L. genei,
if more than one- species is recognized. Professor Vayssieive kindly informs me that he has seen an
unpublished coloured sketch by Verany representing the colour of the animal as “ teinte laque avec
points blancs,” but adds that dead but fresh specimens examined by himself were “ rouge-bruns.”
Verany published a black and white figure (Catalogo degli Animali invertebrati, 1846, pi. ii, fig. 6)
in which the white spots are distinct and circular.
have seen living specimens of L. marmoratus 13 mm. long, which bore little resemblance
to L. genei.
LOMANOTUS G-ENEI V èranv.
(Plate III, figs. 1—8.)
Bergh 11, vi, pp. 5—8, and 12. Vayssière, Moll. Opisth. de Marseille, part iii, 87— 91. Gamble,
Ann. Mag. Nat. Hist., ser. 6, vol. ix, 1892, p. 379.
Hancock made twelve drawings of this species (described as “ Lomanotus portlandicus,
Mr. Vm. Thompson, December 15, 1855 ”) from which figs. 1—6 of Plate III are selected.
Figs. 7 and 8 were drawn from a living specimen caught at Plymouth in 1907.
I have dissected one large specimen from Plymouth Sound, kindly given to me by
Mr. W. I. Beaumont.
The colour of the preserved specimen is yellowish white suffused with brown, which
is deepest on the pericardium, rhinophores, oral veil, mantle-margin with papillm, and on
the tail. There are no white dots. Some, but not all, of the papillm have Colourless
transparent tips.
The length is 26 mm., the breadth at most 8 mm., and the height 9 mm., including the
raised margin. This margin starts from the rhinophore sheaths and is 2—3 mm. wide. It
bears thirty-two papillge on the right, and thirty on the left side, and is bent into six
undulations, three upwards and three downwards. The largest papillge are those in the
centre of these undulations and are about 4 mm. high; the rest are about half the size.
The papillse are distinctly spoon-shaped, the convex surface being generally outside, but
sometimes inside. At the base of the larger papillge are two folds on the inside. The margin
is entire round the tail and forms a horizontal fin. The anus is 15 mm. from the anterior
end, and the genital orifices are 6 mm., just behind the rhinophores. The oral veil bears
four distinct digitations, two on each side, about 2 mm. long. The rhinophore sheaths are
about 3 mm.high; the right bears five digitations; the left, though apparently uninjured,
has only one. The sheaths are slit in front, and the margin is reflexed at the sides and
behind. The foot is produced into short pointed angles and is grooved. The upper
lamina is much stronger and thicker than the lower.
The jaws are yellow, rather soft and flexible, and much as described by Bergh. The
margins for some distance inwards are covered by a mosaic of plates or scales with denticulate
edges. The masticatory process is very short.
The radula corresponds in general with the descriptions of Bergh and Vayssière. It
consists of thirty-two rows. The teeth are large, crowded, and yellow at the sides of the
rows; smaller, spaced, and colourless in the centre. In this specimen, and in all the
smaller ones examined, the radula has a great tendency to break and become confused, and
it seems impossible to spread it out evenly. I t is hard to say whether there is a central
tooth or not, as the arrangement appears to be not quite symmetrical. Down the rhachis
run four or five irregular and not quite straight rows of very irregularly shaped teeth
(Fig. 7 a), bearing a central cusp and three to seven pointed denticles of various sizes on
either side. To the right and left of these teeth the rows become more regular, and then