ivhich inhabit Jamaica. 157 



distinct ; outer peritreme moderately expanded, except on the 

 left side, which is not reflected : umbilicus small. 



Mean divergence about 38°; length .62 inch; greatest 

 breadth .36 inch ; least breadth .26 inch. 



Inhabits New-Hope, AVestmorcland. 



CvcLOSTOMA Tappanianum. Shell elongate conoid : brown- 

 ish orange, with a paler band below the periphery of the last 

 whorl, with the columella brown : with crowded strong trans- 

 verse strife, and less strongly impressed spiral striae ; spire 

 with the outlines moderately convex, truncated with the loss 



of whorls ; remaining whorls four, slightly convex, with 



a moderately impressed suture: aperture ovate, acute above, 

 with the margin not reflected but sharp : umbilicus indistinct. 



Mean divergence about 30°; length .41 inch; greatest 

 breadth .2 inch ; least breadth .18 inch. 



Named in honor of the Hon. Benjamin Tappan, of Ohio. 

 This species was found in a lot of Jamaica shells in the col- 

 lection of R. Gr. Marshall, Esq., of Morant Bay. 



A variety of Cyclostoma papyraceum has the whorls much 

 abbreviated ; the last whorl is more abruptly rounded, and the 

 aperture is consequently shorter. It may be called abbrevia- 



TUM. 



CvcLOSTOMA perpaludum. This name is given to "No. 

 20," described on page 148. Having seen a considerable num- 

 ber of specimens, all of which very exactly coincide in their 

 characters, I can no longer hesitate to regard it as a good spe- 

 cies, although the operculum is yet unknown. 



CvcLOSTOMA DUBiosuM. This specics differs in one very 

 striking character from C. suturale Sowb. : it w^ants the keel 

 next below the suture, in the place of which there is a de- 

 pression of the upper part of the whorls. AVe have seen seve- 

 ral specimens of tliis species and many of C. suturale, and all 

 of them conform exactly to their respective types. "When the 

 operculum of C. dubiosum shall have been found, additional 

 peculiarities may be discovered. 



