TUBICOL^. 453 



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

 faeces. I have found a muscular gizzard in them(l). 



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

 bella alveokUa, Gm.; Tuhipora arenosa, L. ; Ed. XII, Coral., 

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

 orifices regularly arranged like the cells of a honey-comb(2). 

 Another, the 



Arnph. 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 



Syphostoma, Otto, 



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

 ciculus of fine setae, and on the inferior a simple seta, and on the 

 anterior extremity two fasciculi of strong golden coloured setae. 

 Under these setaceous appendages is the mouth, preceded by a 

 sucker surrounded by numerous soft filaments, which may very poss- 

 ibly be branchiae, and accompanied by two fleshy tentacula. The 

 knotted medullary cord is seen through the skin. They live buried 

 in mud(3). Hitherto, the genus 



Dentalium, 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. Deshayes especially(4), have, however, rendered 

 this classification extremely doubtful. 



The animal of the Dentalia has neither any sensible articulation 

 tior. lateral setae, but is furnished anteriorly with a membranous 

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

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

 flattened head, and plumose branchiae are observed on the nape. If 



(1) The Sabellahije, Lam.; the HEKMELiiE, Savigny. 



(2) This is perhaps the place for the ^mphitrite plumosu of Fab., Faun. Groenl., 

 p. 288, and Mull., 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 

 Pherusa, Blainville. 



(3) Siphostoma diplochaitos. Otto; Siph. uncinata, Aud. and Edw., Litt., de la 

 Fr., Annel., pi. ix, f. 1. 



(4) Monograph of the genus Dentalium, Mem. de la Soc. d'Hist. Nat. de 

 Paris, t. II, p. 321. 



