COELOCENTRUM, SUBG. SPARTOCENTRUM. 55 



Alt. 24.5, diam. of last whorl above aperture 4.5, longest axis 

 of aperture 4.5 mm. ; diam. of second whorl of the apex 1.7 mm. 



High table-land of the interior of Lower California, espe- 

 cially about Muleje (W. M. Gabb). 



Cylindrella irregularis GABB et al. in part. Ccelocentrum 

 minorinum var. gabbi PILS., Proc. A. N. S., Phila., 1900, p. 

 551 (Nov. 10, 1900). 



Compared with C. irregulare Gabb, this form is somewhat 

 more attenuated, with the latter part of the last whorl project- 

 ing free, the aperture more oblique and of a wholly different 

 form, strongly resembling that of Berendtia taylori. The rib- 

 lets are more slender and threadlike. It differs from C. 

 digueti in being smaller, with fewer whorls, without sculpture 

 between the riblets, and with scarcely any observable twist to 

 the columella. It is evidently more nearly allied to C. 

 minorinum; but the riblets are arcuate rather than (( fere rec- 

 tilineis;" only the third and fourth whorls have spiral granu- 

 lose striae; the last whorl can hardly be said to be "versus 

 suturam angulato, dor so obtusissime carinato;" the aperture 

 is not "paidulum obliqua," but decidedly oblique. Whether 

 these differences indicate specific or varietal distinction can- 

 not well be decided in the absence of a figure or dimensions of 

 Mabille's species, or of specimens for comparison. 



The specimens were confused by Gabb with his C. irregu- 

 laris. 



C. EISENIANUM Pilsbry. PL 13, figs. 20, 21, 22 ; pi. 17, fig. 25. 



Shell excessively slender and lengthened, the upper half 

 much attenuated, retaining the apex in adult individuals; 

 thin, rather fragile, light brown. Whorls 21-22, the first glo- 

 bose, the second slightly wider, then decreasing slightly in 

 calibre to the fifth ; the earlier 4% whorls thus forming a pu- 

 poid or slightly club-shaped nepionic portion, below which the 

 diameter slowly increases ; last 4 or 5 whorls of nearly equal 

 diameter. All whorls strongly convex ; the last whorl a trifle 

 flattened peripherally, its latter third becoming free and devi- 

 ating tangentially somewhat, the free portion carinated above, 

 having a cord-like keel around the umbilical region below. 



