FAMILY 10. PURPURIFERA. 207 
Pl. CCLL. Fig. 6. 
SrromBus DENTATUS, Linnzus, Syst. Nat., p. 1213. Chemnitz, Conch., 
vol. x. p. 157. f. 1501 to 1503. 
Strombus tridentatus, Lamarck. Sowerby. 
Var. Strombus Samar, Chemnitz. 
PL. CCLI. Fig. 7. 
SrROMBUS FISSURELLA ? Linneeus, Syst. Nat., p.1212. Sowerby, Genera 
of Shells, No. 20. Sowerby, Jun., Thesaurus Conchyliorum, pl. 8. 
f. 64 and 65. 
Rostellaria fissurella? Lamarck. 
Var. Strombus cancellatus ? Lamarck. 
Pl. CCLI. Fig. 8. (fossil.) 
Srromsus pecussatus, Defrance. Sowerby, Genera of Shells, No. 20. 
Family 10. PURPURIFERA. 
Testa vel in canalem brevem, subascendentem, vel in sinum profundum, 
posticé recurvum, desinens. Operculum corneum, interdum nullum. 
The family of the Purpurifera, which includes a very large portion of 
the Gasteropodous mollusks, agrees as nearly as possible with the well- 
known genus Buccinum of Linnzeus ; their shells are chiefly distinguished 
from those of the Canalifera by terminating either with a short, somewhat 
ascending canal, or with a posteriorly recurved sinus ; and they present 
in some instances a considerable anomaly of appearance. The Magilus, for 
example, after forming its shell for two or three whorls in the usual man- 
ner, is obliged to pursue a nearly straight instead of a revolving growth, 
to prevent its becoming totally imbedded ; and there are many little pe- 
culiarities in the shell of Trichotropis which will be duly noticed. There 
are few indications of any varices in the shells of this family, except in 
