| OCR Text |
Show 346 :MOLLUSCA. A multifidous glandular o1·gan opens behind the genital orifices; there is no vestige of a shell. Pleurob. Meckelii, Leve, Diss. de Pleur ., 181 S( 1 ). The only species known; from the Mediterranean. APLYSIA, Lin.(2) The margin of the foot turned up into flexible crests, surrounding the back, and even susceptible of being reflected over it; the head supported by a neck more or less long; two superior tentacula ex· cavated like the ears of a quadruped, with two flattened ones on the edge of the lower lip; the eyes above the former. The branchire are on the back, and consist of highly complicated lamellre attached to a broad membranous pedicle, covered by a small membranous man· tie, in the thickness of which is a flat and horny shell. The anus opens behind the branchire and is frequently concealed under the lateral crests; the vulva is before on the right, and the penis pro· jects from under the right tentaculum. The seminal fluid is con· due ted in coitu, from the penis to the vulva by a groove, which ex· tends from one to the other. An enormous membranous crop leads to a muscular gizzard, armed internally with cartilaginous and py· ramidal corpuscles, which is followed by a third stomach sown with sharp hooks, and by a fourth in the form of a crecum. The intes· tine is voluminous, and the animal feeds on fucus. A limpid hu· rnour, secreted by a particular gland, and which in certain species is said to be extremely acrid, is exuded through an orifice near the vulva, and from the edges of the mantle oozes an abundant liquid of a deep purple colour, with which, when in danger, the animal tinges the water for a considerable extent. The ova are deposited in a kind of long, interlaced, glairy net work, of extreme tenuity. In the seas of Europe we have: .!lpl.fasciata, Poiret; Hang.Apl., pl. vi, vii. Black; margined with lateral red crests; one of the large species. .!lpl. puncta/a, Cuv.; Ann. du Mus. tome II, P· 287, pl. I, f. 2-4; Rang, Apl., pl. xviii, f. 2. Lilac, sprinkled with green· ish points. (1} It is the genus Pleurobranchidium of Blainv., Malac., pl. xliii, f. 3; but not as he thinks the Pleurobrancltus tuberculatus of Meckel. (2) A7rAIJIJ'Ja., which cannot clean itself,-a name given by Aristotle to certain Zoophytes. Linn<eus erroneously applied it as above. The animals here spoken of were well known to the ancients, who styled them Sea·Hares, and attributed to them many fabulous properties. GASTEROPODA TECTIBRANCIIIAT~. 347 .B.pl: depilctns: L.; ~obatch., Anim. Mat·. pl. i and ii; Rang, pl. xvi. Blackish, '":Ith lat·ge greyish, clouded spots. Several other spectes are found in distant seas( 1 ). DoLABELLA, Lam. The Dolabellre only differ from the Aplysire in the position of th branchu· E an d t h e1· r surrounding envelope; they are at the posterioer extremity 'of the body, which resembles a truncated cone. Their Jate~al ct·est presses closely. on their branchial apparatus, merely leavmg a narrow furrow; the1r shell is calcareous. They are found in the Mediterranean and in the Indian Ocean(2). NoTARcnus, Cuv. The lateral crests united and covering the back, a longitudinal emargination excepted, that leads to the branchire, which have no mantle to cover them, but are otherwise like those of the Aplysire; the restoftheir organization is always the same(3). In the BuRsATELLA, Blainv. The lateral crests are united in front in such a manner as only to leave an oval aperture for the transmission of water to the branchire, which are also deprived of a protecting mantle( 4). These two genera, however, probably form but one. (1) .flplysia brasiliana, Rang, pl. viii, l, 2, 3;-.d. dactylomela, Id., IX;-.d. prolea, Jd., X, 1;-.d. sorez, Id., X, 4·, s, 6;-.0. tigrina, Id., XI;-.0. maculata, Id. XIT, 1-5;-A. marmorata, Blainv., Journ. de Phys., Janv., 1823, Hang, XII, 6, 7;-.11. Keraudrenii, Id., XIII;-.0. Lessonii, Id., XIV;-.d. camelus, Cuv., Ann. du Mus., and Rang, XV, 1 ;-.d. alba, Cuv., lb., and Rang, XV, 2, 3;-A. napolitana, Id., XV, bis;-A. virescens, Risso, Hist. Nat. Mer., pl. 1, 7. It is well, however, to observe, that most of the Aplysire having been drawn from specimens preserved in spirits, the truth of the specific characters of some of them may be doubted . (2) DolalJella Rumpltii, Cuv., Ann. du Mus., V, xxix, 1; and Rumph. Thes. Amb., pl. x, 6, from the Molluccas, or .Oplysia Rumpltii, Rang, pl. i;-.dpl. ecaudata, Rang, pl. ii;-.0. truncata, Id. ;-Jl. teremidi, Id. III, 1;-Jl. gigas, IU., Ill, 4;-.11.. Hasseltii, Id., XXIV, 1. (3) Notarchus gelatinosus, Cuv., to which M. Uang associates the Buraatella Sa· ~iana, Descr. de l'Eg ., Zool., Gaster., pl. ii, f. 1, 2, and Rang, .dpl., pl. xx, and h1s .ll.pl. Pleii, pl. xxi, and some small species. (4) Bursatella Leachii, lllainv., Malac., pl. xliii, f. 6. .N.B. Authors have also approximated to the Aplysice the .Opl. vi:ridia, Montag., Lm. Trans., VII, pl. vii, which forms the genus AcTJEON of Oken, and which is at least closely allied to the Elysie timide, Hisso, Hist. Nat. Mer., IV, pl. i, f. 3, 4; as I am not acquainted with the branch ire of either, I cannot class them. |
