VERMETUS. 357 



Shell usually fixed, tubular, whorls often carinated, ir- 

 regular and tortuous ; aperture round, peritrerae acute, 

 continuous. 



Syti. Vermetus, part, Aitct. 



Ex. S. giganteum, Quoy and Gaimnrd, pi. 38, fig. 7. 

 Shell, S. carinatum, Quoy and Gaimard, fig. 7, a. 



Like other members of this family, the animal of this 

 genus is unable to crawl or glide, on account of the shell 

 being fixed, and the foot, not being necessary for locomo- 

 tion, is, in consequence, rudimentary and obsolete. 



Species of Siphonium. 



carinatum, Quoy and Gabn. reticulatvim, Quoy and Gaivi. 



giganteum, Quoy and Oaini. Tonganum, Quoy and Gaim. 



Genus VERMETUS, Adanson. 



Operculum lai-ge, rather concave, whorls very thin, 

 with the external edge produced ; scar central, circular, 

 with close, regular, concentric grooves. 



Shell tubular, conical, when young, usually spiral, when 

 adult, the whorls more or less disunited, the last pro- 

 longed and irregularly twisted ; aperture circular, peri- 

 treme continuous, acute. 



Syn. Serpula, Scop., not Linn. Tulaxodes, Guett. 

 Scolissedium, Rein, Vermicularia, Lam. Vermicularius, 

 Monif. Conchoserpula, Blainv. 



Ex. V. lumbricalis, Linnaus, pi. 38, fig. 8. Opercu- 

 lum, V. Hindsii, Gray, fig. 8, a, 8, h. 



The genus Vermetus was first made known as a Gas- 

 teropodous Mollusk by the researches of the illustrious 



