194 CLAVATOE. 



cc. With, pale bands at suture and periphery. 



C. watersi, no. 3. 



&&. Spire convexly-conic above; suture distinctly 

 margined; size large. C. eximius, no. 9. 



aa. Diameter of shell exceeding one-third its length. 

 &. Large species, 80-150 mm. long; spire convexly 

 conic above, suture with a distinct, narrow mar- 

 gin ; later whorls weakly decussate. 



C. eximius, no. 9. 



&&. Smaller, 50-70 mm. long; spire more straightly 

 conic. 



c. Diam. about half the length of the shell; 

 spire straightly tapering. C. heimburgi, no. 8. 

 cc. Diam. decidedly less than half the length; 

 spire thicker. 

 d. 66 x 24 mm. ; whorls 8 to 9. 



C. davator, no. 6. 

 dd. 53 x 21 mm. ; whorls 7. 



C. johnsoni, no. 7. 



Group of C. obtusatus. 



Shell conspicuously striped with chestnut on a yellow 

 ground, the later whorls not spirally striate; columellar Up 

 ~built forward above the umbilical fissure. 



1. C. GRANDIDIERI (Crosse et Fischer). PL 49. fig. 29. 



Shell subrimate, oblong, rather thin, longitudinally im- 

 pressed with rather widely spaced striae, not decussate. Spire 

 long-pyramidal, the apex rather obtuse; suture crenulate- 

 margined. Whorls 8, rather flat, the last slightly ascending, 

 nearly half the total length. Aperture oblong-pirif orm ; 

 columella vertical, straight, receding. Peristome simple, the 

 margins distant, somewhat converging, columellar margin 

 very much dilated, very broadly reflexed over and closing 

 the umbilical chink and reaching a width of as much as 10 

 mm. in the widest part. Basal and outer margins reflexed, 

 somewhat thickened outside. Length 95, diam. 31, aperture 

 37 mm. long, 23 wide (C.etF.). 



