218 BULLETIIN 181, inSTITET) STATES NlAfTIODSriAiL MUSEUM 



by a thick callus, which is separated from the preceding turn by a 

 slender groove which renders the peritreme complete. Operculum 

 typically neocyclotid, having 7 whorls. 



The specimen described and figured, U.S.N.M. No. 192951, was col- 

 lected by H. Pittier in the Eio Frio Basin, Sierra Nevada de Santa 

 Martha Mountains, at an altitude of 1,200 meters, San Andres, Colom- 

 bia. It has 4.5 whorls and measures: Height, 20.1 mm.; greater 

 diameter, 31 mm.; lesser diameter, 20 mm. Height of aperture, 

 14.6 mm.; diameter, 14.9 mm. 



This species resembles A. (N.) sancfaemarthae Pilsbry and Clapp, 

 from which it can be distinguished readily, however, by its exceed- 

 ingly deeply and broadly channeled suture and by its larger aperture. 



APEROSTOMA (NEOCYCLOTUS) SANCTAEMARTHAE Pilsbry and Clapp 



Plate 29, Figubes 22-24 



1902. Aperostoma sanctaemarthae Pilsbby and Clapp, Nautilus, vol. 15, pp. 



134-135, pi. 7, figs. 9-10. 

 1923. Poteria (Neocyclotus) sanctaemarthae H. B. Bakek, Occ. Pap. Mus. Zool. 



Univ. Michigan, No. 137, p. 43. 



Shell helicoid, covered with a broad, rather dark chestnut-brown 

 periostracum ; interior of aperture pale buff with a bluish tinge. The 

 nucleus consists of 2 moderately large, well-rounded, smooth turns. 

 The postnuclear whorls are well rounded and marked by slender, 

 wavy, somewhat vermiculated, retractively curved axial ribs. Suture 

 strongly impressed, with a slight narrow channel on the last quarter 

 of the last turn. Periphery strongly rounded. Base narrowly umbili- 

 cated, inflated, strongly rounded, and marked by the continuation of 

 the axial ribs, which grow into rather strong riblets on the umbilical 

 wall. Aperture circular, slightly angulated at the posterior angle; 

 peristome simple, the outer lip moderately thickened; the inner a 

 little more so. A moderately straight callus covers the parietal wall, 

 from which it is separated by an impressed line, thus rendering the 

 peritreme complete. Operculum typically neocyclotid, showing 7 

 volutions. 



The type, Carnegie Mus. No. 62.15065, comes from Las Nubes Estate, 

 4,000 feet elevation, Santa Marta Mountains, Colombia. It has 4.3 

 whorls and measures : Height, 19.5 mm. ; greater diameter, 31.4 mm. ; 

 lesser diameter, 21.2 mm. Height of aperture, 13.4 mm.; diameter, 

 14.4 mm. 



This species is nearest related to A. (N.) corpulentum, (E. A. 

 Smith), from which it can be readily distinguished by its much 

 less channeled suture and smaller aperture. 



