13 



Mean divergence 35°; length .83 inch; greatest breadth .45 inch; 

 least breadth .35 inch. 



36. Cyclostoma pauperatum. Shell very elongate and slender, 



conic; color ?; very coarsely striated transversely, not crenula- 



ted in the suture, spiral lines wanting ; spire with nearly rectilinear 

 outlines ; apex truncate with the loss of three (?) whorls ; five whorls 

 remaining, with a moderately impressed suture ; aperture ovate-orbicu- 

 lar ; inner peritreme on the right side less elevated above the outer 

 one, which is moderately expanded, concave, sharp, produced into an 

 angle and inflected at each extremity of the left side ; umbilicus very 

 small, concealed by the lip. 



Mean divergence 28°; length .58 inch ; greatest breadth .20 inch; 

 least breadth .2 inch. 



37. Helicina palliata. Species similar to H. Bimvnii, Gray, but the 

 shell is larger, thicker, less globose, with the incision as deep but much 

 narrower and linear ; the produced columella is grooved with a 

 broad shallow furrow, while in H. Brownii it has a deeply impressed 

 line. 



The characters of the incision and produced columella in this 

 group of HelicinsB appear to be very constant. It is chiefly for this 

 reason that I regard this as a good species. The form and size are 

 intermediate between H. maxima and H. Brownii. 



Mean divergence 110°; length .43 inch ; greatest breadth .69 inch; 

 least breadth .55 inch. 



38. Helicina Hollandi. Species similar to H Brownii, but the 

 shell is much smaller and thinner ; it is chiefly distinguished by the 

 incision being only half as deep, and by the produced columella, 

 which has no impressed line nor groove, although slightly raised at 

 the margins. 



Mean divergence 105°; length .23 inch; greatest breadth .41 inch ; 

 least breadth .32 inch. 



39. Helicina macilenta. Shell rather small and thin, subdiscoid- 

 al, flattened beneath ; pale brown ; epidermis extremely thin, micro- 

 scopically hirsute or chagrined ; spire a little elevated and convex ; 

 whorls nearly four and one-half, scarcely convex ; aperture large ; 

 labrum thin, sharp, moderately expanded and reflected, with a deep 

 curved incision below the columella similar to that of//, palliata; 

 the produced columella is strongly margined on the inner side. 



Mean divergence about 135° : length .16 inch; greatest breadth .29 

 inch ; least^breadth .23 inch. 



40. Helicina albolabris. Shell with a notch Jike that of//, inax- 

 ima, but the notch is rather large proportionally ; in other respects 



