B. CLADOHEPATICA.
The liver does not form a single mass but is divided, and in the majority of families
ramified. In the first nine families given below the radula is not ascoglossan, and jaws
are invariably present.
F amily gg PLEUROPHYLLIDIIDiE.
See especially Bergh 4, which is a monograph on the family.
A very distinct family which has apparently been specially modified for a burrowing
life. Animals of a fair size, flat, oval or tongue-shaped, and of leathery consistency.
Head with a tentacular shield behind which is a sort of neck bearing retractile rhino-
phores. No dorsal appendages. The margin of the mantle usually bears cnidopores, and
underneath it are usually branchial lamellse. Radula broad, jaws strong, liver ramified.
Genus 1. Pleurophyllidia Meckel.
Cnidocysts and branchial lamellse are present. The anterior pallial margin forms a
continuous fold behind the rhinophores, and in front ^of them there is usually a special
prominence known as the caruncle.
1. PI. loveni B ergh.
(.Pt. 8, PI. VIII, figs. 8—10.) ^
See Bergh 15.
No other species is recorded with certainty from the northern Atlantic. The
occurrence there of the Mediterranean species P. undulata (= lineata) is doubtful though
not improbable. P . mulleri is known from Brazil, and several species are reported from
South Africa. Pleuroleura (== Dermatobranchus) walteri Krause is recorded from
Spitzbergen. This genus resembles Pleurophyllidia in most points but has no lamellse
beneath the mantle-margin nor branchiae of any kind.
F amily II. DENDRONOTIDJE.
Limaciform animals with oral veils and dorsal appendages which are usually
branched and sometimes arborescent. Rhinophores retractile into projecting sheaths.
Radula moderately wide or narrow. Liver divided into three portions, which commonly,
but not invariably, send branches to the dorsal appendages.
Genus 1. Dendronotus A. & H.
See Bergh 18, pp. 136—144; 24, pp. 25—33; Herdman and Clubb, Second Report on Nudib.
of L. M. B. C. District, Trans. Liverpool Biol. Soc., vol. iii, p. 225; Clubb, in ditto, vol ix 1895
pp. 220—234.
Animals of large or moderate size. The oral veil and rhinopliore sheaths bear
arborescent processes. Rhinophores perfoliate. On either side of the back a single row
of arborescent cerata. Radula varying from about 6.1.6 to 21.1.21. Liver consisting of
a large posterior mass and two smaller anterior portions.
The hepatic diverticula extend into the cerata in some cases, but not in others. The
genitalia are unarmed. The hermaphrodite gland is large, and lies above the posterior
liver. Prostate present.
1. D. frondosus (Ascanius).
(Pt. 1, Pam. 3, PI. 3.)
2. D. lacteus (Thompson).
Thompson, Ann. Nat. Hist., v. 5,1840, p. 88; Becher, Moll, von Jan Mayen,
1886, p. 14.
[3. D. robustus V errill, 1870.
. = II* velifer G. O. Sars, 1878.
See Verrjll, Amer. Joum., i, 1870, p. 405; id., Procjfc S. Nat. Mas., ii, 1879, pp. 197—198 -
id., Catalogue of Marine Molluscs added to Fauna o».New England, Trans. Connect. Acad., y, S
1882, p. 550; G. O. Sars 1, pp. 315—316; Bergh 50, pp. 141—144.]
I t seems a pity that a name so familiar to British marine zoologists as Dendronotus
arborescens should be altered. I t rests on the authority of O. F. Müller, who described
Boris a/rborescens in 1776. Bat there can be little doubt that this animal is the same as
the Amphitrite frondosa described by Ascanius in K. Norske Videnst. Selskabs Skrifter.,
Heel v, p. 155, pi. y, fig. 2, 1774, and this specific name has priority.1
B. buteobus Lafont in Actes Soc. Linn. Bordeaux, tom. xxviii,..187], p. 267, is
probably a variety of this species. Becher considers B. lacteus to be separate, since it
differs in dentition as well as coloration.
B. robustus is recorded from both sides of the. northern Atlantic; . but not as yet
from British waters. I t is as much as 90 mm. long, and red with white dots. The oral
veil is very large with numerous short processes which bear knobs but are hardly
branched. The rhinophore sheaths bear five almost simple processes. There are seven
pairs of cerata, lower and smaller than in B. frondosus, with a small appendage on the
outside near the base. Jaws rather shorter and broader than in B. frondosus. Eadula
from about 30 X 15.1.15 to 35 x 20.1.20. Median teeth with prominent central cusp
and fifteen to twenty side dentieles, Lateral teeth with very irregular
1 I t is used m the hat of Plymouth Marine Invertebrate Eauna, published in the J.B.M.A.,
1904. I t is a blessing that no one proposes to substitute Amphitritetor Dendronotus.