195 



straight canal ; base with two or three smooth spiral 

 ridges . f . . . 0,0 1 1 . Skeerness and Devon . 



GENUS. PLEUROTOMA. 



Turreted or Fusiform ; terminating below in a more or 

 less elongated and straight canal ; outer lip with a 

 transverse fissure or notch near the suture. 

 P. GRACILIS. F. p. 354. MUREX G. Mont. p. 

 267. and Sup. p. 586. t. 16. f. 5.D. p. 742. Lin. 

 T.S.p. \4'3.Dor. Cat. p. 46. t. 14./. 18. M. 

 EMARGINATUS. Don. t. 169. /. 2. Slender, tapering 

 to a fine point, yellowish with lighter and brown bands ; 

 whorls little rounded, with eleven or twelve very convex, 

 obtuse longitudinal ribs interrupted at the suture by a 

 depressed spirally striated space, the spiral stria? at the 

 base strong and rather distant ; aperture oval, canal mo- 

 derately long, rather open. ^...i. Deep water, not 

 vjicommon. 



P. SINUOSA. F.p. 354. MUREX S. Mont. p. 264. 

 t. 9./ H. Lin. T. 8. p. 145. D.p. 745. Strong, 

 thick, white ; whoris six, tapering to a fine point, little 

 convex, with seven longitudinal, strong, much elevated 

 and arched ribs which do not extend to the fine suture, 

 finely and regularly striated transversely, the striae most 

 conspicuous in the interstices ; aperture narrow and 

 i 2. 



