COELOCENTRUM. 39 



of the shell consists of fine, close flat riblets wider than the in- 

 tervening grooves except on the last whorl, where they are 

 narrower. Fig. 24 of pi. 14 represents the sculpture of the 

 fourth whorl up, fig. 25 of the last whorl. 

 Var. CLAVA (Pfeiffer). PL 12, figs. 11, 12, 13, 14; pi. 14, figs. 



26, 27. 



Shell deeply arcuate-rimate, turreted-cylindric, truncate, 

 rather thin, closely arcuate-striate, diaphanous, but slightly 

 shining, tawny. Spire a little tapering above, rather widely 

 truncate. Whorls remaining 16-21, moderately convex, the 

 last shortly free, carinated above and at the base, and with a 

 thread-like keel at the side. Aperture squarish-oval, chan- 

 nelled at the base, columellar fold slight, deep ; peristome con- 

 tinuous, white, expanded and a little reflexed throughout. 

 Length 42-57, diam. 9-10 mm. ; aperture with peristome 8 mm. 

 long, 7 wide (Pfr.). 



Chiapas, Mexico ( Ghiesbreght) . 



Cylindrella clava PFR., P. Z. S. 1856, p. 380 ; Malak. Blatter 

 1856, p. 217 ; Conchyl. Cab., p. 36, pi. 8, f . 11, 12 ; Monogr. iv, 

 p. 696 ; vi, 365. BLAND, Ann. Lye. N. H. of N. Y., viii, p. 160 

 (1865). SOWERBY, Conch. Icon, xx, pi. 13, f. 115 a, lCcdo- 

 centrum clava Pfr., FISCH. & CROSSED Moll. Mex. i, p. 346, pi. 



15, f. 14. STREBEL, Beitrag, iv, p. 57, pi. 5, f. 10; pi. 14, f. 8. 

 v. MARTENS, Biologia, p. 270, with var. rufescens, p. 271, pi. 



16, f. 2 (Nov., 1897). 



"Very near C. turris but smaller, varying in total length 

 from 40 to 57 mm., and in the breadth of the penultimate 

 whorl from 9 to 10 mm. Number of preserved whorls 15-20. ' ' 



Pfeiffer 's description is given above, and his type figures 

 are copied on pi. 12, figs. 11, 12, representing a specimen with 

 the maximum number of whorls and largest size mentioned in 

 the original description. This narrow, markedly cylindric 

 form must be considered the type. A smaller specimen, also 

 narrow, is figured by Strebel from Pfeiffer's collection. On 

 pi. 14, figs. 26, 27, 1 figure a Chiapas specimen in the collection 

 of the Academy. It is corneous- white, with only 12 whorls, 

 and measures, length 32%, diam. Sy 2 mm. 



Another specimen is light reddish-brown, with 13 whorls 



