3 



o. CycLOSTOMA AMANDUM. Shell short, globose-conic ; dingy white 

 with three principal and often other brown more or less interrupted 

 spiral bands; with quite regular prominent lamellre of growth, which 

 are decussated and aculeated by very numerous close-set spiral lines, 

 that appear only on the last three whorls and are most conspicuous 

 just below the suture ; spire with very convex outlines ; apex trun- 

 cate with the loss of two whorls ; three and one half remaining, very 

 convex, with a deep suture ; last whorl a little detached from the 

 penult whorl near the aperture, but soldered to it by the outer 

 peritreme; aperture exactly circular, inner peritreme much pro- 

 duced, regularly striated on the outside parallel to the edge ; outer 

 peritreme finely scolloped with the termination of the spiral lines ; 

 umbilicus extending through to the truncate apex, and exhibiting all 

 the whorls. 



Mean divergence 88° ; length .55 inch ; greatest breadth .6'} inch ; 

 least breadth .43 inch. 



0. Cyclostoma Blandianum. Shell like C. lima, Ad. but the spiral 

 lines are less distinct, and both the spiral and transverse lines are 

 finer and more closely set; the shell is shorter and the whorls are nar- 

 rower ; color pale brown to white, with more or less distinct interrupt- 

 ed spiral brown lines ; outer peritreme very much expanded, especially 

 on the left side, slightly crenulated, above produced into a broad sinus ; 

 umbilicus narrow and extending through the truncate apex. 



Mean divergence 60° to 62° ; length .7 inch ; greatest breadth .65 

 inch: least breadth .45 inch. 



7. Cyclostoma VARiABiLE. Shell moderately elongate, ovate conic; 

 deep blackish blue when fresh, fading by exposure into pale yellowish 

 brown, and then developing on the upper whorls two and on the last 

 whorl three somewhat interrupted spiral brown lines and intermediate 

 series of small brown spots, with a series just below the suture of large 

 square spots, with a wax-yellow lip ; with very fine spiral striae on the 

 last three whorls, decussated by very close-set rounded ridges of 

 growth, most of which are gathered in the suture into minute white 

 crenulations ; spire with very convex outlines; apex truncate with the 

 loss of three to three and one half whorls; four whorls remaining, 

 which are quite convex and very slightly angular above the middle, 

 with the suture rather deep ; aperture circular ; outer peritreme at 

 first rather thin smooth, and polished ; in the old, the lip is filled be- 

 tween its moderately produced inner and outer margins with a solid 

 deposit concentrically striated, not scolloped; umbilicus small, exhibit- 

 ing but a part of the last whorl, extending through the truncate apex. 



Mean divergence 43° ; length .53 inch ; greatest breadth .34 inch ; 

 least breadth .'26 inch. 



