130 PROCEEDINGS OF THE NATIONAL MUSEUM. voi, xxxi. 



which is restricted to this vokition, appearing only as a strong twist in 

 the last and in the anteponiiltimate turns. The parietal, basal, and 

 peripheral lamella3 are also confined to the penultimate whorl. The 

 parietal one is large and very strongly outward curved, the free edge 

 bent toward the peripheral lamella, which forms a strong; keel and is 

 located al^out one-third the height of the chamber above the floor. 

 The basal lamella is thick and strong and apposes the outer edge of 

 the columellar fold and not the parietal one as is usually the case. 

 Two narrow slits are thus formed, one between the parietal and 

 peripheral fold, the other between the columellar and basal folds. 



The unique type, Cat. No. 187650, U.S.N.M., was collected by 

 E. W. Nelson in the Sierra Guadelupe, Coahuila, Mexico. It has 13i 

 whorls and measures: Length 9.T mm.; diameter of tenth whorl 2.9 

 mm.; diameter of penultimate whorl 2.7 mm. 



The diminutive size and the very regular cylindric outline distin- 

 guish this species from all the other known Ilolospiras. 



HOLOSPIRA (HOLOSPIRA) PAINTERI, new species. 

 Plate III, fig. 5. 



Shell small, pupoid, flesh colored to light brown. Nuclear whorls 

 two, well rounded, shining, very minutel}^ granulose. Succeeding 

 whorls rather inflated, those of the conical portion decidedly rounded, 

 the rest rounded on the posterior third between the sutures, the lower 

 two-thirds becoming flattened and somewhat contracted anteriorly. 

 Penultimate whorl somewhat lower than the rest and well rounded. 

 The entire surface is marked by well developed, regular, and regularlj'^ 

 spaced obliquely backward-slanting riblets. These riblets are a little 

 more crowded on the middle of the spire than on the cone; in general, 

 they will average about one-half the diameter of the spaces that sepa- 

 rate them; this, however, docs not hold on the last two turns; here 

 the}' are decidedly more distantly spaced. The type has about 67 ribs 

 upon the fifth, 86 upon the eighth, and 60 upon the penultimate 

 whorls. Periphery of the last whorl ver}' slightly angulated. Base 

 3'ellow horn-color, imperforate. Both periphery and base are 

 crossed bv the riblets which continue into the umbilical rimation. 

 Last whorl free and built out for about one millimeter. The free 

 portion is crossed by sublamellar riblets, which form a series of wavy, 

 concentric rings, that become closely crowded behind the peristome. 

 The solute portion of the outer wall is concaved in the middle and the 

 parietal wall is decidedly pinched about one-fourth of the way to the 

 left of its junction with the outer wall. This renders the posterior lat- 

 eral angle keeled, and gives to the aperture a channeled appearance at 

 this place. Aperture well rounded anteriorly, having the parietal and 

 lateral walls somewhat sinuous. The parietal and columellar folds are 

 both visible deeply within the aperture. Peristome decidedl}' ex- 



