292 



OL1VA. 



>%M ] VOLUTA PORPHYRIA.— LimiCLUS. 



^ | Sowerbys Genera, No. 8, pi. 2. 



Lamarck has constituted of these shells a distinct ge- 

 nus from that of the G. Voluta, to which Linnaeus had 

 assigned nearly all of them, under the title of Voluta oli- 

 va, as if they were merely varieties of one species, not- 

 withstanding that many of them are most distinctly cha- 

 racterized. They cannot be confounded with the Voluta 

 or the Mitra, the shells of those genera not having their 

 spiral whorls separated by a canal; in addition to which 

 the left side of the aperture or columella of the Oliva 

 presents, at its upper extremity, a projecting callosity, 

 concurring in the formation of the spiral canal, which 

 so strikingly marks these shells; the columella has al- 

 so at the base vestiges of the very oblique callosity, 

 which indicates their alliance with the Ancillariae, 

 though in that genus there is no canal at the spire, and 

 the columella is never plaited. Shell subcylindrical, 

 convolute, and smooth; the last whorl concealing all 

 the others, as in the G. Conus; spire short; sutures ca- 

 naliculated; aperture longitudinal and narrow, notch- 

 ed at the base; columella obliquely striated its whole 

 length. It is presumable that the animal inhabiting 

 the shells of this genus constructs its dwelling in a 



