PLEUROTOMA. 165 



the keel-rib, and somewhat larger size and proportionally longer 

 canal will distinguish it from the last species. 



P. ALBINA, Lamarck. PI. 2, fig. 14. 



Keel-rib flattened, bearing a row of equidistant, somewhat- 

 quadrangular brown spots, the rest of the surface very minutely 

 and numerously punctate with brown. L. 58, diam. 15 mill. 



Moluccas. 



The conspicuous painting on the slit-band, contrasted with 

 the very minute sprinkling of brown dots elsewhere, is the 

 distinguishing characteristic of this species. 



P. GRACILLIMA, Weinkauff. PL 2, fig. 15. 



Shell spirally ribbed, the second rib from the sutures crenu- 

 lated,the third prominent; white, sparsely maculated with chest- 

 nut. L. 36, diam. 9 mill. 



Habitat unknown. 



Distinguished by its narrow, graceful form, and crenulation. 



P. MARMORATA, Lamarck. PI. 2, figs. 16, 16 a, 17. 



Shell rather sharply carinate on the shoulder, encircled by 

 narrow small, sharp ribs and intermediate raised lines; white, 

 usually thickly maculated in a longitudinal manner with chestnut- 

 brown, sometimes minutely punctate with chestnut. 



L. 75, diam. 21 mill. 



Eed Sea, Malacca, Japan, Australia, Polynesia. 



The usual appearance of this species is represented by fig. 16 ; 

 occasionally it is spotted, and sometimes it is entirely devoid 

 of coloring. P. hastula, Reeve (fig. 17), is the young of this 

 species. 



P. PEASEANA, Bunker. PL 2, fig. 18. 



Shell carinate, with a pair of prominent ribs at the suture and 

 other less prominent ribs and raised lines throughout ; yellowish, 

 flammulate with brown. L. 25, diam. 7 mill. 



Indian Ocean. 



A young shell, which may possibly prove to be identical with 

 P. Garnonsii, Reeve. 



P. TJNEDO, Valenciennes. PL 3, fig. 20. 



Shell angularly turreted, with concavely sloping shoulders 

 defined by duplicate granular ribs, forming the angle ; every- 



