12 



PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 70 



HOLOSPIRA (HOLOSPIRA) PEDROANA, new species 



Plate 1, fig. 3 



Shell large, cylindro-conic, very pale brown, almost white. Nuclear 

 whorls 2.5, well rounded, marked by very fine granules, forming a 

 truncated cylindrical apex. Postnuclear whorls increasing slowly 

 in size, well rounded, marked by very distantly spaced, low, rounded, 

 retractively slanting axial ribs which are strongest on the early turns. 

 On the middle turns they become almost obsolete and very far apart. 

 On the last two whorls they again become stronger and on the last 

 they are almost lamellar. The last whorl is decidely contracted to- 

 ward the base. Suture well impressed. Periphery of the last 

 whorl well rounded. Base rather short, narrowly umbilicated, 

 marked by the continuations of the axial ribs. The last third of the 

 last whorl is decidedly solute with a very strong angle behind the 

 posterior angle of the aperture, and an obsolete angle behind the 

 junction of the inner and parietal wall. The solute portion is 

 marked by very irregular more or less fused axial riblets which en- 

 circle the whorls. Aperture subtriangular, parietal wall somewhat 

 sinuous, peristome decidedly expanded and strongly reflected. The 

 internal pillar is slender, somewhat twisted in the last turn and with- 

 out columellar fold here. In the penultimate turn and the turn 

 preceding this, a slender, columellar fold is apparent. In the ante- 

 penultimate whorl also the strongly outturned parietal wall is present 

 iind well developed. Here, too, a short basal fold is apparent, and a 

 very weak labial fold is present in the narrow gap between the two. 



The type (Cat. No. 362176 U.S.N.M.) was collected by C. K. 

 Orcutt under agave in the hills north of San Pedro, San Luis Potosi, 

 Mexico. It has 17.2 whorls and measures — length, 20.9 mm.; 

 diameter, 4.4 mm. 



Four paratypes (Cat. No. 362177 U.S.N.M.) yield the following 

 measurements : 



HOLOSPIRA (HOLOSPIRA) TOPOCHICOANA, new species 



Plate 1, fig. 5 



Shell rather large, milk white. Nuclear whorls 2^/^, well rounded, 

 forming a narrow blunt cone. Postnuclear whorls flattened with 

 the summit almost appressed, the first marked by rather 

 strong retractively slanting distantly spaced axial riblets which be- 



