248 BEY. B. B. WATSON ON THE 



Fam. CiECiD^:. 

 Gen. Cjecum, Flem. 



15. C^CUM ATLANTTDIS, XX. Sp. 



Shell very small, thin, transparent, of a dull glossy white, 

 a good deal bent, subannulated. Sculpture : there are towards 

 the tip a few sparse, somewhat feeble, but rather sharply 

 topped, encompassing rings, which die out on the concave curve 

 of tbe shell ; one or two similar but feebler rings appear 

 near the mouth ; on the intermediate space undulations rather 

 than rings are traceable ; the whole surface is marked by faint 

 lines of growth, and excessively minute, sharp, densely crowded 

 microscopic longitudinal striae. The apex is closed by a flat 

 somewhat impressed plate, from the forward side of which pro- 

 jects a short, blunt, laterally compressed triangular ping. The 

 mouth, which is circular, is neither contracted nor patulous. 

 Operculum thin, impressed, brown, with circular lines of growth. 

 — L. 0-085. B. 0022. 



C. vitreum, Carp., is larger than this species, and lacks its 

 sculpture and circular rings, and has contraction of the lip. The 

 plug in C. atlantidis is like that of C. trachcea, Mont., but the shell 

 is much smaller than in that species ; the circular rings are not 

 close-set but are well parted ; their tips are not flattened but 

 sharp or rounded. C. atlantidis, without being rare, is certainly 

 not common, and was not found in the collections of Lowe, 

 McAndrew, or Johnson. I got it only at Porto Santo. For the 

 beautiful figure of this species I am indebted to the Marquis de 

 Folin, who was kind enough to draw it for me. 



Fam. Naticidjs. 

 Gen. Natica, Adans. 



16. Natica (Nacca) furva, n. sp. 



Shell white, with two dark smoky bands which are some- 

 times absent but sometimes occupy nearly the whole shell, which 

 is pretty strong, depressedly conical, with a small but a little 

 raised spire and rounded whorls ; the last of these is large, with 

 an open mouth ; a continuous white porcellanous pad fills the 

 upper part of the mouth and nearly chokes the umbilicus. 

 Sculpture — Longitudinals none, but lines of growth which, 



