46 



CASSIS. 



C. nuperus. Subglobose, with spiral impressed strife, and fine longitudinal 

 lines; whorls of the apex convex, and cancellated; coiumella with pro- 

 minent tranverse lines, obsolete in the centre; labrum thickened with ir- 

 regular prominent lines on the submargin. 



PLEUROTOMA. 



P. elaborate. Subulate, with numerous oblique elliptical nodules, and spi- 

 ral impressed stria;; beak very short, aperture small; emargination of the 

 labrum profound. 



P. hilmliita. Turrited or scalariform volutions eight; cancellated with 

 flue stria', the spiral ones most distinct; angle of the whorls somewhat ca- 



rinated; profoundly umbilicatcd. 

 P. alternata. Su 



Subulate or subfusiform; cancellated; spiral, stria} distinct; 

 middle of each whorl cmiulated; beak somewhat produced. 



P. (fcpygtK. Subulate, with nine angulated volutions, nodulous in the 

 middle: and with line rounded spiral stria;; beak very short. 



P. Hiipera. Fusiform, with eight angular volutions, crenulatcd in the 

 middle, and fine spiral wrinkled stria); body whorl slightly veutricose; 

 shoulder with oblique crenulations, beak somewhat produced. 



NATI-CA. 



N. /#.'*. Subglobose, spire very short, umbilicus large, contracted by 

 the callus, and with a prominent, obtuse, broad carina revolving within it; 

 aperture semilunar. 



. N. emiinilu. Obovate, with smooth convex volutions and a prominent 

 conical spire; umbilicus elliptical, not contracted by the callus; aperture 

 obovate, rather more than half the length of the shell. 



X. liinvla. Obliquely suboval, smooth, with a short convex spire; um- 

 bilicus nearly closed by a profound callus; aperture elliptical. 



X. elurca. Smooth and polished; spire slightly prominent, with convex 

 whorls; body whorl subcom pressed ; umbilicus minute, with a groove be- 

 neath it; aperture small, circular. 



PYKAMIDKLLA. 



P. liiffntit. Subulate, with nine smooth volutions, indented at the sutures, 

 the indentation margined above by a slightly prominent line; body whorl 

 with a spiral indented line near the middle; fold on the coiumella prominent. 



MITKA. 



M. jmrtilf*. Subfusiform, with seven volutions, a single row of nodules 

 on each, except the two from the apex, which are smooth; apex 'papillated; 

 spire elevated; coiumella with four folds'; aperture nearly half the length 

 of the shell. 



M. jtercj-ilin. Narrow-fusiform, with seven smooth convex volutions; 

 base strongly striated; aperture contracted; less than half the Icjigth of the 

 shell; coiumella with three plaits. 



NUCULA. ' 



N. f(jn<ili*. Convex, with obtuse central beaks, anjl 'regular concentric 

 ntriiu; anterior end slightly recurved, with a carinatcd submarginal lino. . 



N. ofnilenta. Elongated, compressed, with regular concentric sulci; an- 

 terior side rostrated, and with a submarginal (-urinated line; space between 

 it and the margin with regular prominent stria", beaks posterior to the mid 

 die. 



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