156 Descriptions of New Species and Varieties of Shells, 



The operculum is similar to that of C. album, being sub- 

 spiral, with oblique strisB. 



Variety album wants the dark brown color, and has the 

 spiral dotted lines more or less indistinct. 



Variety virgatum is dingy or ])earl white, with the spiral 

 dotted lines conspicuous. 



This species is named in honor of the botanist M. Chevalier. 



Cyclostoma album, var. fuscum, is distinguished by its 

 smaller size, brown color, and a less smooth surface. 



CvcLosTOMA Yallahense. This species resembles C. hya- 

 cinthinum (p. 9), which is probably identical with C. Bank- 

 sianum Sowb. But it is smaller and more slender ; the color 

 is bluish brown, and does not change by age or exposure into 

 orange near the aperture; the striae are coarser ; the oblique 

 indentations are, often obsolete. The operculum is similar to 

 that of C. hyacinthinum. 



Mean divergence about 46° ; length .48 inch ; greatest 

 breadth .32 inch ; least breadth .27 iticli. 



Although this shell so mnch resembles the species with 

 which we have compared it, a peculiar type is easily recog- 

 nized in it. The two types are geographically remote ; this 

 species inhabiting the east end of the island from Yallahs' 

 Hill eastward, while the other occurs in the middle of the 

 south side (Manchester) and westward. Neither species has 

 been found in the intermediate regions. 



Cyclostoma sericinum. Shell much elongated, conic : 

 silky white, with four spiral series of brown dots, of which 

 three appear on the spire ; around the umbilicus is a fifth se- 

 ries less distinct : with crowded regular transverse obtuse fine 

 raised lines : spire with the outlines moderately convex, trun- 

 cated with the loss of two whorls ; whorls remaining four and 

 one-half, quite convex, with a rather deep suture : aperture 

 slightly detached from the penult whorl ; inner peritreme in- 



