226 BULLETIN 181, lINITEiD STtATES NiATIO0S[tA)L MUSETOkl 



the peritreme complete. Operculum typically aperostomid, having 

 about 8 whorls. 



The type, U.S.N.M. No. 251169, was collected by H. Pittier in the 

 valley of the Rio Paez, in the Central Cordilleras, Colombia. It 

 has 4.5 whorls and measures : Height, 20.9 mm. ; greater diameter, 37.3 

 mm.; lesser diameter, 26.3 mm. Height of aperture, 13.8 mm.; 

 diameter, 17.7 mm. 



In the open umbilication, this species resembles A. (J..) urribili- 

 catmn, from which it is easily differentiated by its color scheme and 

 the much larger aperture, as well as the much finer sculpture. 



APEROSTOMA (APEROSTOMA) BOGOTENSE (Pfeiffer) 



Plate 31, Figtjkes 4-6 



1855. Cyclostoma (Cyclotus) hogoiense Pfeiffee, Proc. Zool. Soc. London, vol. 



23, p. 117. 

 1858. Cyclotus hogotensis Pfeiffer, Monographia pneumonomoporum viventium, 



vol. 2, p. 17. 

 1863. Cyclotus bogotensis Reeve, Conchologia iconica, vol. 14, sp. 20. 

 1897. Neocyclotus (Neocyclotus) togotensis Kobelt and Mollendobff, Nachrb. 



deutschen malak. Ges., vol. 29, p. 137. 

 1923. Poteria (Neocyclotus) bogotensis, H. B. Bakeb, Occ. Pap. Mus. Zool. 



Univ. Michigan, No. 137, p. 44. 



Shell small, depressed-helicoid, varying from olivaceous to oliva- 

 ceous-brown, with a dark zone at the periphery and usually a nar- 

 row light one above it. The base is bicolor, that of the posterior 

 half being olivaceous, while the anterior half is much paler ; interior 

 of aperture bluish white. The nucleus consists of 2.3 rather large, 

 well-rounded, smooth turns. The postnuclear whorls are well 

 rounded, the last one being slightly flattened below the surmnit and 

 marked by strong, small malleations, which give the upper surface 

 of the shell not only a malleated but a somewhat vermiculated aspect. 

 The last whorl is slightly decurrent on the last quarter of the turn. 

 Suture very strongly impressed. Periphery weakly angulated. Base 

 moderately broadly umbilicated, somewhat inflated, well rounded, 

 and marked by almost vertical, irregular, incremental lines, which are 

 a little stronger on the umbilical wall, and feeble malleations. Aper- 

 ture circular with a slight angulation at the posterior angle; peri- 

 stome simple, the outer lip thin, the inner slightly thickened posteri- 

 orly. The parietal wall is covered by a thick callus which renders 

 the peritreme complete. 



The specimen described and figured is one of three, U.S.N.M. No. 

 316133, which comes from Bogota, Colombia. It has 3.8 whorls and 

 measures: Height, 13.3 mm.; greater diameter, 20.5 mm.; lesser 

 diameter, 14.7 mm. Height of aperture, 9.2 mm. ; diameter, 9.4 mm. 



U.S.N.M. No. 524128 contains 1 specimen without specific locality. 



