LIOTIINiE. 403 



Ex. C. sulcata, Martyn, pi. 45, fig. 3. Operculum 

 C. sulcata, fig. 3, a, 3, h. Shell, C. sulcata, fig. 3, c. 



This genus appears to be intermediate between Astra- 

 Hum and Bolma, but does not quite accord with either. 

 M. Lesson founded it upon the Turbo Cookii of Gmelin, 

 so named after the great circumnavigator, but the specific 

 name of Martyn has priority ; the species comes from 

 New Zealand. 



Genus BOLMA, Risso. 



Operculum ovate, sub-orbicular, convex, with a sub- 

 central tubercle over the axis, and a broad, sub-marginal, 

 spiral rib. 



Shell turbinately trochiform, elevated, rugose, axis im- 

 perforate ; aperture circular ; inner lip wide, flattened, 

 excavated, covered with a thickened callus. 



Ex. B. rugosa, Linnmis, pi. 45, fig. 4. Operculum, 

 B. rugosa, fig. 4, a, 4, h. Shell, B. rugosa, fig. 4, c. 



In this form the periphery of the whorls is rounded, 

 and the aperture is circular ; the inner lip being covered 

 with a thick callosity is another peculiarity. 



Species of Bolma. 



aurea, Jonas. obtusa, Chem. 



gibberosa, Gmel. rugosa, Linn. 



modesta, Reeve. 



Sub-fam. LIOTIIN^. 



Operculum horny, with an external calcareous coat 

 formed of separate, pearl-like, shelly particles placed in 

 spiral lines. 



