132 ANNELIDES. 



tube bent towards the head, which doubtless afibrds an issue to the 



faeces. I have found a muscular gizzard in them*. 



Such is the species foimd along the coast of France, the Sa- 

 bella alveolala, Gm. ; Tuhipora arenosa,h.; Ed. XII, Coral., 

 XXXVl.. Its tubes, united in one compact mass, have their 

 orifices regularly arranged like the cells of a honey-comb f. 



Another, the 



Amph. ostrearia, 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 



Sypiiostoma, Olto, 



Where, on the superior part of each articulation, is inserted a fasci- 

 culus of fine setae, a*id on the inferior a simple seta, and on the ante- 

 rior extremity two fasciculi of strong golden coloured sctsc. Under 

 these setaceous appendages is the mouth, preceded by a sucker sur- 

 rounded by numerous soft filaments, wliich may very possibly be 

 branchiae, and accompanied by two flesliy tentacula. The knotted 

 medullary cord is seen through the skin. They live buried in mud J. 

 Hitherto, the genus 



Dextai.U'M, Liii,, 



Has always been placed in this vicinity. Tlie 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. Deshayes especially §, have, however, rendered this 

 classification extremely doubtful. 



The animal of the Dentalia, lias neither any sensible articulation, 

 or lateral setoe, but is furnished anteriorly with a membranous 

 tube, inside of which is a sort of foot, or fleshy and conical opereu- 

 liun, which closes its orifice. On the base of this foot is a small 

 flattened head, and plumose branchiae are observed on the nai)e. If 

 the operculum recall to our minds the foot of the Vermeti and Sili- 

 quarise, whicli have been placed among the MoUusca, the brane]ii;e 

 strongly remind us of those of the Amphitrites and Terebellas. 

 Ulterior observations upon their anatomy, nnd principally upon that 

 of their nervous and vascular system, will resolve this problem. 



* The Sabkllari.e, Lam. ; the Hf,rmki,i„e, S;ivigny. 



t This is perhaps the place for the Aiiipld/ri/c plunwsa of Fab., Faun. Gro2nl., 

 p. 288, and Mi'ill., Zool. Dan., xc ; but their descriptions are so obscure, and agree 

 so little with each other, that I dare not attempt to assign it. It forms the genus 

 Phercsa, Blainville. 



I Siphosioma diplochaitvs, Otto; — Siph. mcinata, Aud. and Edw., Litt., de la Fr., 

 Annel., pi. ix, f. 1. 



§ Monograph of the genus Dentalium, Mem. de la Soc. d'Hist. Nat. de Paris, 

 t. II, p. 321. 



