1st Sub-order. Anthrobranchbs.
1st Fam. (Les Doris.* Doris, Onohidoris, Polycera.
2d Sub-order. P olybranchks.
2d Fam. ‘Les TH to n ie sTritonia, Doto, Thetys, Soyllsea.
8d Fam. (Les Glauques* Laniogera, Glauous, Eolis, Tergipes.
This is, in its essential points, the arrangement of the present day; very little alteration
having been made beyond the addition of the genera since discovered. The arrangement of
Blainville is that of Ferussac with an alteration of names. His orders f* Cyclobranches and
“Pol (/branches'’ are the two sub-orders above mentioned; and his families “Diceres and Tetracres,
in the latter order, correspond with' the Tritonies and Glauques of Ferussac: these orders,
however, were placed nearly the last in a descending series. Rang added two new families, Les
Pterosomes and Les Placobranches: the former appears rather to belong to the Nucleobranchiaia.
We find in the British Museum Catalogue for 1840, the Gymnobranchiata (Nudibranchiata)
comprises the following families:—1, Dondce; 2,. Tritonida; 3, Placobranchidee; 4, Phyllidiadce;
5, Patellida; 6, ChitonicUe. The two latter families have been withdrawn in Dr. Gray’s
subsequent arrangements, whicl\ we shall have to notice afterwards. M. D’Orbigny also,
includes the Placofoanchida and JDiphyllidiadce in his order Nudibranchiata published in 1842*
The next arrangement we shall notice is that of M. de Q-uatrefages (1844). In conformity
with his views on the anatomy of these animals, he detached the Eolididee from the
Nudibranchiata, leaving that order to consist of the Doridida and Tntoniada alone, and
established a new order, Phlebenterata, in which he includes the Eolididee, the Placobranchida
of Rang, and a few small genera without special breathing organs, mostly new. His
arrangement of the order Pheleb en tera ta is as follows:
Gasteropodous Mullusca with an imperfect circulation or none, and without respiratory
organs properly so-called.
Fam. 1. Intestine ramified, and prolonged into the external appendages. E nterobranches.
Tribe 1- Appendages isolated, more or less numerous. Enterobranches proprement dit.
Eolide, Eolidine, Zephyrine, Amphorine, CalliopSe, Cavoliue (?), Glaucus (?), &c.
Tribe 2. Appendages united in the form of oars. Enterobranches remibranches.
Acteon, Acteonic, Placobranche (?), &c.
Fam. 2. Intestine very simple, in the form of a few pouohes; no external appendages.
Dermobranches.
Pavois, Chalide.
In the first part of the present work (1845) we arranged the British species then known
in the following order:
Fam. 1. Do kid in.«. Branchial plumes surrounding the vent on the medio-dorsal line.
Sub-Fam. •Doridinee, with a cloak.
Doris, Goniodoris, Triopa.
Sub-Fam. Polycerinte, without distinct cloak.
.ZEgirus, Thecacora, Polycera, Idalia.
Fam. 2. T ritoniad,b. Branchire, laminated, plumose or papillose, arranged down the sides of
the back; stomach entire.
Tritonia.
* In his * Paléontologie Françoise/
Fam. 3. Eounin.«. Branchire papillose or branched, arranged on the sides of the back;
stomach branched.
Sub-Fam. Melibmna. Tentacles 2, with sheaths.
Dendronotus, Doto.
Sub-Fam. Eolidinee. Tentacles without sheaths, 2, 4, or none.
Eolis, Pterochilus, Hermsoa, Alderia, Proctonotus.
Professor Allman, in his paper on the anatomy of Actaxm,* proposed a modified arrangement
of the Nudibranchiatc Mullusca, which we subjoin.
Section. Family. Genera.
rB ranch ire in the mesial line placed in a circle,')
more or less complete, round the anus, r Doris, Polycera, &c.
Liver compact ■! Dorididte. )
Branchire arranged along the sides or soattered. j Scyliiea, Thetis.
I Tritoniad<e. )
f Branchire papillose, or branched, or muricated.) Eolis, Alderia, Dendro-
Liver disintegrated j Eolididee. ) notus, Glaucus, &c.
v Branchire foliaceous. Actneonidce. Actteon, Placobranchus ?
But the most extensive arrangement of the order yet published, is that of Dr. J. E. Gray,
in Mrs. Gray’s * Figures of Molluscous Animals.’ In this work the distribution of the whole of
the known species into genera and families has been attempted. This, it must be
acknowledged, is a very difficult task, with the present imperfect descriptions of foreign
species; and we do not think that, in all cases, Dr. Gray has succeeded in his details, but as
that distinguished naturalist has superseded this arrangement by another in a late number of
the ‘Annals of Natural History,’! it is unnecessary to enter into any further description of it
on the present occasion.
The classification now proposed by Dr. Gray, is founded upon the characters afforded by
the spines of the tongue taken in conjunction with the breathing organs, and is as follows:
1. Gills suri'ounding the vent on the middle of the hinder part of the back.
Fam. 1. Onchidoridj«. Teeth 2 in each cross series; gills iu separate cavities; mantle edging
the foot and simple.
AcanthodoriSy Onchidoris.
Fam. 2. DoRiDiDA£»Doridina and Polycerina, Gray. Teeth many in each cross series, , subsimilar,
inner often smaller; gills in a common cavity; mantle edge simple.
a. Doris; |3. Goniodoris, Ceratosoma; y. ASgires.
Fam. 3. TriopidjE=— Triopina, Gi'ay. Teeth many (rarely only 4) in each cross series, inner
lateral ones large, irregular-shaped; gills in a common cavity; mantle small, edged
with tentacles.
Triopa, Idalia.
* Ann. Nat. Hist., v. 16, p. 145. t lb. 2d Ser., v. 11, p. 218.