10 



Mean divergence 58° ; length .58 inch ; greatest breadth .45 inch ; 

 least breadth ,35 inch. 



Probably this is a variety of C. Banksianum, which is more coarsely 

 and conspicuously crenulated ; but without authentic specimens of C 

 Banksianum, I am unable to decide from the description and figures 

 in the Thesaurus. 



27. Cyclostoma Redfieldianum. Shell ovate-conic ; pale blueish 

 gray or dingy white, with a few spiral interrupted lines of dark brown ; 

 strongly striated transversely, without spiral striae ; spire with rather 

 convex outlines; apex truncate with the loss of two whorls ; three and 

 one-half quite convex whorls remaining, with a deep suture, which 

 has a few strong unequal inequidistant crenulations ; aperture large, 

 nearly orbicular; inner peritreme a little produced and reflected ; 

 outer peritreme wanting on the upper part of the left side, much 

 expanded on the remaining part of this side, moderately spread on the 

 outer side, concave, sharp-edged, above often inflected so as to form a 

 cell ; umbilicus small. 



Mean divergence 55° ; length .66 inch ; greatest breadth .5 inch ; 

 least breadth .4 inch. 



28. Cyclostoma tectilabre. Shell ovate-conic; blueish horn 

 colored, with several interrupted spiral brown lines; with rather closely 

 set sharp elevated transverse lamella, without spiral striae ; spire with 

 quite convex outlines ; apex truncate with the loss of two and one-half 

 very small whorls ; nearly four very convex whorls remaining, with a 

 deep suture, aperture a little detached from the penult whorl, nearly 

 orbicular, slightly angulated above : inner peritreme very slightly 

 spread, but covering the outer one, which is extremely small ; umbili- 

 cus small. 



Operculum much larger than the aperture, with its margin reflected 

 abruptly far behind the margin of the aperture ! 



Mean divergence 45° ; length .53 inch ; greatest breadth .4 inch ; 

 least breadth .3 inch. 



29. Cyclostoma armatum. Shell much elongated ; brown, with a 

 reddish and cinereous tinge, usually darker at the summit, rarely with a 

 spiral series of dark brown spots ; with very closely set strong trans- 

 verse raised lines (the whitish color of which gives the ashy tinge to 

 the general aspect), which at the upper extremity are enlarged, mostly 

 in fours with one unenlarged line between, into a closely set series of 

 strong sutural crenulations, — without spiral striae ; spire with outliri'^s 

 scarcely convex; apex truncate with the loss of two and one-half 

 whorls ; five moderately convex whorls remaining, with a well im- 

 pressed suture ; last whorl near the end a little detached from the pre- 



