314 SHELLS AND SHELL-FISH. 



SuB-FAM. 4. PLEUROTOMIN^. 



Shell turreted, subfusiform ; the base channeled, and 

 often much produced ; outer lip never thickened, but 

 detached at the top from the whorl by a slit or sinus.* 



Bbachytoma t Sw. Subfusiform ; resembling a small 

 Strombus or Fusus ; spire and aperture of equal 

 length j channel short ; outer lip slightly ascending, 

 and forming a short canal ; sinus very small, and 

 nearly semi-circular ; inner lip thickened above. 



strombiformis. Sow. Man. castanea Sw. Chem. f.l831, 

 f. 381. 14^/2. 



Pleurotoma Lam. Fusiform, turreted ; channel 

 lengthened, and nearly as long as the spire ; the slit 

 long and narrow ; inner lip wanting. 



P. virgo. En. Meth. 439. Babylonica. lb. f. 1. 

 f. 2. Javanica. lb. f. 3. 



Clavatula Sw. Spire clavate, very long, turreted ; 

 channel short ; inner lip wanting. 



sulcata Sw. Chem. 190. f. 1829. 



Clavicantha »S'w. Thick, sub-fusiform ; the surface 

 rugose, and the whorls sub-coronated ; channel short ; 

 slit assuming the form of a short broad sinus. 



C. imperialis. En. Meth. conica. E. M. 439. f. 9. 

 440. echinata. lb. 439. f. 8, 



spirata. lb. 440. f. 5. auriculifera. lb. f. 10. 



ToMELLA Sw. Fusiform, smooth ; the spire of very 

 few whorls, and not longer than the channel ; inner 

 lip with a thick callosity at the top ; the slit short and 

 wide. 



lineata. En. Meth. 440. f. 2. filosa. En. Meth. 440. f. 6. 

 clavicularis. lb. f. 4. lineolata. lb. f. 1 1 . 



* In the two typical groups, the'notch is a long slit ; in the three aberrant 

 genera, it forms a wide but short sinus. 



+ The aberrant species of this genus connects the sub-family with the 

 Columbellince by means of Crassispira. They are mostly small and rare 

 shells. 



