Genus 2. Ancula L ovIsn.
See Loveii, Index Mollusc., 1846, p. 5; Bergh 20, pp. 3—9; Meyer and Mobius 1, pp. 59—61.
Body limaciform, smooth. No oral veil or pallial margin, but the place of the latter
is marked by a row of papillae in the branchial region. Oral tentacles distinct. Rhino-
phores perfoliate, not retractile, without sheaths, but with two tentacular appendages.
Branchiae few (three), tripinnate. Verge armed with hooks. Buccal crop sessile. Strong
labial armature of hooks. The rhachis of the radula bears thickenings which do not
amount to teeth; on either side are two teeth, the inner large, broad, and denticulate,
the outer smaller and plain.
3. A. cristata Alder.
(Pt. 3, Fam. 1, Pl. 25.)
[•Ancula sulphured, from the coast of New England, described by Stimpson, Inverte-
brata of Grand Manan, 1858, p. 26, is probably only a large variety of this species.
The genus Drepania, created by Lafont in Journ. de Conchyl., xiv, 1874, p. 369, for
D. fusca found at Arcachon, is nearly allied to Anculd, but has (a) only a single appendage
on each rhinophore; (6) a single papilla near the branchiae; (c) two small labial plates; (d)
no outer teeth in the radula, so that the formula is simply 1.0.1.]
Genus 3. Idalia L euokart.
See F. S. Leuckart, Breves animalium quorundam . . . Deseriptiones, 1828, p. 15; Bergh 22,
pp. 140—181.
Body high, foot broad, and prolonged into a tail ; dorsal surface small. Pallial margin
prominent and bearing a row of more or less elongate papillæ all round. Over the
mouth an oral veil produced on either side into an indistinct tentacular expansion.
Rhinophores perfoliate, not retractile. Branchiae simply pinnate, usually rather numerous
(ten to eighteen). Penis armed with hooks; prostate large. Buccal crop sessile. A small
labial armature of hooks is present. Formula of radula 1 + 1 . 0 . 1 + 1. Inner teeth
large, hamate, smooth or denticulate ; outer small, flat, but generally with indications of
a hook or spine.
The genus has been divided by Alder and Hancock, followed by Bergh, into two
sections: {a) Idalid sensu stricto in which the centre of the dorsal surface bears papillæ,
the labial armature is a ring, and the inner teeth are smooth or minutely denticulate; and
(6) Idaliella Bergh, in which the centre of the back is smooth, the labial armature consists
of two plates, the inner teeth are*strongly denticulate, and the outer teeth hooked.
(Idalia sensu stricto.)
1. I. elegans L euokart.
(Ft. 7, Fdm. 1, PI. 27.)
2. Idalia leachii A. & H.
(Pt. 7, Fam. 1, PI. 27.)
(Idaliella.)
3. I. aspersa A. & H.
{Pt. 1, Fam. 1, PI. 26.)
4. I. inaequalis F orbes.
Perhaps merely a variety of No. 3. See Garstang 1, p. 186.
5. I. pulchella A. & H.
var. fusca Odhner 1, p. 101.
Idalia quad/ricornis (Montagu) can hardly be identified and had better be omitted
from the list.
[Family IV. C0RAMBID.E.
See H. A. Adams on Hypobranchisea fusca in Proc. Zool. Soc., 1847, p. 24; Verrill on Doridella
obsev/ra, in Amer. Journ. of Science, 1870, vol. 1, p. 408 ; Bergh on Gorambe sargassicola, 5, pp. 21—25;
Kerbert on Gorambe batava, in Tijdschrift der Nederlandsche Dierkundige Vereiniging, Dl. 1, Af. 2,
pp. 5—6, 1886; H. Fischer, Recherches anatomiques sur un Mollusque Nudibranche appartenant
au Genre Gorambe- {G. testudmaria), 1891, Ball. Sci. France et Belgique, xxiii, 1891; and Balch on
Gorambella depressa, in Proc. Boston Soc. Nat. Hist., vol. xxix, 1901, pp. 151—153.
It is not easy to say how many of the above genera are valid. Hypiobranchisea and
Doridella are so imperfectly described that it is better to neglect them, at any rate
provisionally, and make Gorambe the type of the family, which is well defined in most
points. The members of it are small (3—5 mm.), flat, elliptical, doridiform animals with
retractile rhinophores, a compact liver, a labial armature (as a rule), and a narrow radula
without a central tooth. But they differ from nearly all known Holohepatica in having
the vent and branchiae at the end of the body and under the pallial margin, the branchiae
consisting of a few lamellae arranged on either side of the vent. The genital orifices are
on the right side and only one spermatotheca has been found. Molluscs belonging to this
family are recorded from the Zuider Zee, Arcachon, the Sargasso Sea, and the Atlantic
coast of the United States. I t is therefore probable that they are found in the British
area, but have escaped notice on account of their minute size.
Gorambe Bergh. Pallial margin notched at the posterior extremity above the
branchiae. A labial armature.
1. G. testudinaria Fischer, from Arcachon. Brownish. Radula 4 + 1.0.1 + 4.
First lateral large and denticulate; the rest much smaller.
Gorambella Balch, from the Atlantic coast of North America, is said to have the
mantle-edge even all round and not notched, and also to have no labial armature.
1. Glia, depressa Balch. Brownish with reticulate markings. Radula 5 +1.0.1 + 5;
first lateral smooth.]