The mouth is between the bases of the two tubercles of the bead. Below it are two triangular tentacula, which form, as it were, two small wings between the two large ones. The opening of the mouth is triangular ; and within are seen some longitudinal wrinkles, which Pallas and Fabricius appear to have taken for teeth, but which have no hardness, and are entirely fleshy. The viscera are connected by vessels and cellulosities which unite them in a small packet situated near the neck. The liver covers the greatest part of them, with th e exception of an angle which is occupied by the testicle and ovary.
The (usophagua, of a fair length, descends from the month through the neck, and is dilated into n stomach towards the bottom of the MASA. Thence the intestinal canal, after having made one fold, pro ceeds directly to the vent. situated under the gill of the left side. The liver is composed of many lobes and lobules, and envelops the stomach and a great part of the intestinal canal. Two long and straight salivary glands float at the sides of the (esophagus; their excretory ducts are inserted in the mouth. (Cuvier.) The brain consists of two lobes placed at the origin of the ceso plingtts. From each of these springs a small filament, which swells into a large ganglion that unites itself to its correspondent tinder the (esophagua. These two ganglions give out each their filaments to the neighbouring parts. Two of these filaments, one on each side, swell again into ganglions, which, uniting together by a new filament that traverses upon the (esophagus, form there a second collar joined to the first beneath ; they give out a filament, which is twice swollen or knotted, and it is from these small knots of medullary matter that the different nerves arise. No eye could be perceived, nor any par ticular organ of the external senses, except the common and general organ of touch. (Cuvier.) Each gill gives off a vein, which, uniting to its correspondent in the shape of a Y, forms the trunk which reaches the heart. Thin last, situated in its pericardium on the left side of the mass of viscera, gives out, doubtless, arterlee for the whole body, but they could not be followed out. (Cuvier.) In the reproductive organs they very much resemble the Gastro pods, and unite, like them, the two sexes. The ovary gives off a delicate and short oviduct, which reaches the testicle. This last, which at its origin resembles a merlin, !mem by degrees into a de ferent canal, and terminates at a mall round purse, which fills the left tubercle of the head, and has its exit near the neck. It is unde
termined whether the straight and firm part which terminates the deferent canal is the male organ, or whether that organ is hidden in the small purse above noticed. At the side of this purse is another oblong one, analogous to that which is termed the bladder (la vessie) in the ordinary Gastropods. (Cnvier.) Dr. Leach says, " In 1811, during a tour made by me to the Orkneys with some friends, I observed on the rocks on that side of the Isle of Stan, several mutilated specimens of this animal. The three previous days had been extremely stormy so RS to confine us to the Isle of Coluusa. Some days afterwards I borrowed from a fisherman a large shrimp-net, and on rowing Mon the coast of Mull when the sea was calm, after many vain efforts, I was at last enabled to catch one of them alive." This specimen is now In the British Museum ; others are in the Museum of the Royal College of Surgeons.
The figures and description above given (Cuvier's) are taken from an individual which had its tentacula, &c., withdrawn.
O. Specie; without tentacula and whose cephalic enlargement (reufle ment) is separated from the trunk by a sort of narrow and very distinct thorax. (Genus, Cliodiles of Quoy and Gaimard.) Example, Clio (CI iodites) caduceus. De Blainville observes that this species is too incompletely known to allow of a satisfactory conclu sion as to what it is ; and he even thinks that it may be identical with the C. australis of Bruguierea.
Pneumodernion.—Animal oblong, sub-cylindrical, divided into two very distinct parts, the anterior conical, the posterior oval. Tho fins placed near the separation of these two parts, and presenting between them, and on the ventral side, a small membranous appendage. Mouth at the extremity of a sort of retractile proboscis, having, at its base, two bundles of tentacula, each terminated by a small disc or sucker. Gills situated at the posterior part of the body, and disposed some what in the form of two C'e placed back to back, OC, and separated by two small bars. Vent on the right, and a little anterior to the gills. Orifice of the organs of generation in a common tubercle, situated at the root of the fin of the right side.
P. Peronii. This is about an inch iu length, and was discovered in the Atlantic Ocean by Pdron. The genus was established by Cuvier. 1)o Manville founded his character upon many well-preserved indi viduals brought home by Messrs. Quoy and Gaimard from the expedi tion under Captain Freycinet, and gives Australasia as the locality of the species.