252 Lamarck's Genera of Shells. 



Type. Dclphinula laciniata *. (Turbo dclphinus. Linn.) 

 Shell subdiscoidal, thick, transversely nidely sulcated ; fur- 

 nished with very large, curved, ramose, jagged appendages ; 

 variegated with red and brown ; spire obtuse. Indian Ocean. 

 Pi. VIII. Fig. 163. — 3 recent species, and 7 fossil. 



10 th Family. 

 TuRBiNACEAf. (8 Genera.) 

 Shell turrited or conoidal ; aperture round or oblong, not 

 dilated ; margins disunited. 



All sea-shells, and appear to be operculated. When placed 

 on their base, the axis is always more or less inclined, never 

 vertical. 



1. Solarium^. 



Shell orbicular, depressed conical ; umbilicus open, always 

 crenate or toothed on the internal margins of the whorls. 

 Aperture subquadrangular ; no columella. 



The crenate umbilicus of the solarium sufficiently distin- 

 guishes it from the trochus and planorbis. 



Type. Solarium perspectivum\. (Trochus perspec- 



tivus. Linn.) 



Shell orbicular, conoidal, longitudinally striated, whitish 

 yellow ; bands articulated with white and brown, or chestnut 

 colour near the sutures ; crenations of the umbilicus very 

 small. Indian Ocean. PI. VIII. Fig. 164. 7 recent species, 

 and 8 fossil. 



2. Rotella||. 



Shell orbicular, shining, no epidermis ; spire very short, 

 subconoidal ; lower face convex, callous. Aperture semi- 

 circular. 



Distinguished from trochus by the lower surface being 

 remarkably callous, and from the helicina by the callous not 

 being confined to the columellar lip, but extending over a 

 large portion of the lower side of the shell. 



Type. Rotella lineolata%. (Trochus vestiarius. Linn.) 



* Jagged. t From iurhinntus, fashioned like a top'/ 



t A sun dial. ^ Perspective. 



II A very small wheel. f Marked uith little lines. 



