NO 1483. 



UR COP TID MOLL VSKS—BA R TSCH. 



117 



this is somewhat sunk, lending it the appearance of a broad, shallow 

 groove. The remainder of the base is well rounded and marked bv 

 the continuation of the riblets which pass undiminished over the 

 periphery and the groove to the umbilical region, where they become 

 decidedly crowded. Last whorl free for about 1^ mm. Aperture 

 suboval, somewhat angulated at the posterior lateral margin and at the 

 junction of the columellar edge and the lip, showing the edge of the 

 obsoletely truncated pillar within. Peristome yellowish white, some- 

 what thickened, decidedly expanded but not reflected. Internal pillar, 

 2.5 mm. in diameter in its widest part, provided with a thickened 

 twist in each whorl about one-fourth the height of the whorl above 

 its base. In addition to this the pillar is marked, posterior to the 

 twist, by irregularly developed, low, rounded, smooth, cord-like, 

 oblique folds or threads; in most instances these are not continuous, 

 but are interrupted, forming a series of low, oval, or elongated pro- 

 tuberances. The space anterior to the twist is smooth. There are 

 two specimens of this species in the collection of the U. S. National 

 Museum Cat. No. 185492, collected by Dr. H. Pittier in the Cave of 

 Sakalkunte, near Senahu, Alta Vera Paz, Guatemala at an altitude of 

 1,800 meters. 



Measurements of Ccelocentrum pittieri. 



a Type. 



Aperture of type from angle to angle, 13 mm., the line at right 

 angles to the center of the above measurement, 10.1 mm. 



These two specimens are in a semifossil state, and partly incrusted 

 with lime deposits. The left border of the figure is slightly obscured 

 by the deposit in our illustration. The shell superficial!}" has the gen- 

 eral aspect of Ccdocentru/n. turris Pfeiffer, but diflers markedl}" from 

 this by its much smaller internal pillar and the sculpture tliereof . 



CCELOCENTRUM PITTIERI GUATEMALENSIS, new subspecies. 

 Plate IV, fig. 11. 



There is one specimen in the collection, Cat. No. 187469, U.S.N.M., 

 collected by Dr. H. Pittier at Secanquim, Alta Vera Paz, Guatemala, 

 at an altitude of 550 metei-s, which agrees most nearly with C. pitt'ttrl^ 

 but ditfers sufficiently to merit a distinct name. It difl'ers from C. 

 pittieri by its smaller size and less tapering earl}^ whorl, and by having 

 the riblets more distantly spaced. The whorls, too, are slightly over- 



