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Show 452 ANNELIDES. AMPHITRITE, Cuv.(l) The Amphitrites are easily recognized by the golden coloured set~, arranged like a crown, or the teeth of a comb, in one or two rows, on the anterior part of their head, where they probably serve as a means of defence, or perhaps enable the animal to crawl, or to collect the materials of its tube. Numerous tentacula encircle the mouth, and on each side of the fore part of the back are pectiniform branch ire. Some of them construct light tubes of a regularly conical figure, which they carry about with them. Their gilded setre form two combs, whose teeth incline downwards. Their capacious and frequently flexed intestine is usually filled with sand(2). Such is the .O.mph. auricoma belgica, Gm.; Pall., Miscel., IX, 3-5. Its tube is two inches long, and formed of variously coloured round granules(3). .IJ.mph. auricoma capensis, Pall., Miscel., IX, i, 2. From the South seas; its thin and polished tube appears to be transvet·sely fibrous, and formed of some desiccated, soft, and stringy sub· stance. It is a luger species( 4 ). There are others which inhabit artificial tubes fixed to various bodies. Their gilded setre form several concentric crowns on their head, from which results an operculum that seals up their tube when they contract, but the two parts of which can sepat·ate. Each foot is furnished with a cinus. The body is terminated behind in a ( 1) This genus, as it stands in Muller, Brugieres, Gmelin, and Lamarck, also includes some Terebellre and Sabellx. ln 1824, Diet. des Sc. Nat. II, p. 78, Ire· duced it to its actual limits; since then, M. Lamarck has changed my divisions into genera, his PECTINARilE and 8ADELLAIU.lE1 termed APIIICTENlE and HERMELLB hy Savigny. The AMPHITRIT:cs of Lamarck are my SAnELLJE. M. Savigny, on the contrary-, makes it the name of a family. (2) They are the PECTINA.RIJE, Lam.; APHICTENJE, Savig.; CJIRYSOlJONTES, Oken; and the CISTEN}(l of Leach. This perpetual changing of names-and in this particular case there was not even the pretext of a change of limits in the group-will finally end in rendering nomenclature a much more difficult study than that of facts. (3) The same as the Sabella belgica, Gm., Klein., tab. I, 5, ~~chinod., xxxiii, A, B, and as the .llmph. auricoma, Mull., Zool. Dan. xxvi, of which Hrugieres has made his .llmphitrite dm·te. ( 4) The same as the Sabella chrysodon, Gm., llerg., Stock. Mem., 1765, IX, 1, 3; as the Sabella capensis, Id., Stat., Mull., Nat. Syst., VI, xix, 67, which is a mere copy of Bergius; as the Sabella indica, Abildgaardt, IJerl. Schr., IX, iv. See also Mart. Slabber, Fless. Mem., I, ii, 1-3. TUBICOLJE. 453 tube bent towards the head, which doubtless affords an issue to the freces. I have found a muscular gizzard in them( I). Such is the species found along the coast of France, the Sabella alveolata, Gm.; Tubi11ora arenosa L . Ed XII c 1 · :r , ·, • , ora., XXXVI. Its tubes, united in one compact mass have their orifices regularly arranged like the cells of a hon~y-comb(2). Another, the .IJ.rnph. ost1·earia, Cuv., establishes its tubes on the shells of Oysters, and it is said greatly hinders their propagation. It is to this order I suspect that we must refer the SYPHOSTOMA, Otto, Where, on the superiot• part of each articulation, is inserted a fasciculus of fine setre, and on the inferior a simple seta, and on the anterior extremity two fasciculi of strong golden coloured setre. Under these setaceous appendages is the mouth, preceded by a ~ucker surroun.ded by numerous soft filaments, which may very possIbly be branch1re, and accompanied by two fleshy tentacula. The knotted medullary cord is seen through the skin. They live buried in mud(3). Hitherto, the genus DENT ALluM, Lin. Has always been placed in this vicinity. The shell is an elongated, arcuated cone open at both ends, and has been compared to the tusk of an elephant in miniature. The recent observations of M. Savigny and those of M. Desha yes especially( 4), have, however, rendered this classification extremely doubtful. The animal of the Dentalia has neither any sensible articulation nor lateral setre, but is furnished anteriorly with a membranous tube, inside of which is a sort of foot or fleshy and conical operculum which closes its orifice. On the base of this foot is a small flattened head, and plumose branchire are observed on the nape. If (1) ·The SABELLARIJE, Lam.; the HERMELLJE, Savigny. (2) This is perhaps the place for the .llmpltitrite plumosa of Fab., Faun. Grrenl., P· 2.88, an~ Mull., Zool. Dan., xc; but their descriptions are so obscure, and agree 80 httle Wtth each other, that I dare not attempt to assign it. It forms the genus Punuu, Blainville. (3) Siplwatoma diploc!taitoa, Otto;-Siplt. uncinata, Aud. and Edw., Litt., deJa Fr., Annel., pl. ix, f. 1. (4) Monogt-aph of the genus DENTALIUM, Mem. de la Soc. d'Hist. Nat. de Paris, t. II, p. 321. |
