CERION, GROUP X. 245 



mainder polished and for the most part faintly sculptured with little 

 raised transverse lines, often obsolete ; on the last half of the last 

 whorl these lines are coarser, irregular and more prominent; the 

 aperture is rounded except where the peristome crosses the body, 

 with a slightly beveled reflected edge; the parietal tooth is nearly 

 central, short and low, the pillar- tooth also low, is situated about the 

 middle of the pillar and makes a little less than a complete turn 

 around the axis of the shell. Height of the shell 28 ; maximum 

 diameter 12 mill. (Dull}. 



Water Cay, Salt Cay Bank, on the north side of Cuba near the 

 western end of the Bahama banks. Types in the Iowa State Uni- 

 versity and National Museums. 



Cerion (Maynardia) niteloides DALL, Bull. Lab. Nat. Hist. Iowa 

 State University, iv, no. 1, p. 15, pi. 1, f. 2 (1896). 



" This species externally much resembles Cerion (Maynardid) niteln 

 Maynard, which is a species native to the west end of Little Cayman 

 island in the Caribbean Sea on the south side of Cuba. As the 

 species of Cerion are very limited in their distribution, the wide sep- 

 aration of the two localities raises a suspicion of distinctness, notwith- 

 standing their superficial likeness, and this suspicion is measurably 

 confirmed by the following differences : C. nitela has a larger axis 

 and a considerably larger and perforate umbilicus ; its parietal tooth 

 is more elevated and less elongated, the pillar tooth slightly more 

 elevated, and its inward prolongation decidedly more feeble; lastly 

 its aperture is narrower, more horse-shoe shaped and less rotund than 

 in C. niteloides. The apex is decidedly more pointed in the speci- 

 mens of C. nitela before me as well as in Maynard's figures, but this 

 character is variable in some of the species." (Dall.') 



X. Group of C. album. 



Robust, strongly ribbed species, closely allied to the group of C. 

 gubernatorium, but ribbed to the apical whorl (except C. lentigi- 

 nosum). Parietal callus appressed, thin at the outer edge. 



The species are from Abaco and Rum Key ; islands not lying on 

 the same bank, but with very similar snails of this genus. 



These species are unlike most of those of the C. glans group in 

 wanting a raised ledge across the parietal margin ; but they are not 

 greatly different. 



