THE CYOLOPHORID LAND MOLLUSKS OF AMERICA 257 



whorls and measures : Height, 16 mm. ; greater diameter, 21.8 mm. ; 

 lesser diameter, 16.3 mm. Height of aperture, 9.4 mm.; diameter, 

 10.3 mm. 



U.S.N.M. No. 316273 contains 2 additional specimens labeled 

 ''Venezuela." 



While this species resembles A. (A.) pazi (Crosse) in having the 

 last whorl deflected, it can be distinguished from it in being much 

 darker in coloration and in havmg the umbilicus narrower. 



APEROSTOMA (APEROSTOMA) PAZI (Crosse) 



Plate 37, Figures 12-14 



1866. Cyclotus pasi Crosse, Journ. Conchyl., vol. 14, p. 356, pi. 14, fig. 3. 



1897. Neocyclotiis (NeocycJotus) poisi Kobelt and Moixendorff, Nachrb. deutschen 

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



1923. Poteria (NeocycloUis) pazi H. B. Bakeb, Occ. Pap. Mus. Zool. Univ. Michi- 

 gan, No. 137, p. 41. 



Shell small, helicoid, covered by an olivaceous periostracum, the 

 early whorls of which have a brownish tinge. There are irregular 

 streaks of darker axial bands present. There is a narrow pale zone 

 immediately posterior to the periphery and a weak brownish band 

 about one-quarter the width of the base anterior to the periphery. The 

 rest of the base is horn colored ; interior of aperture bluish white. The 

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

 The postnuclear whorls are strongly rounded; the summit of the last 

 one falls very materially below the periphery of the preceding turn. 

 The postnuclear whorls are marked by fairly strong, retractively slant- 

 ing axial riblets, which are about as wide as the spaces that separate 

 them. On the last half of the last turn these riblets become very 

 irregular, more or less fused, and quite obsolete on the last portion. 

 Periphery obsoletely angulated. Base moderately broadly umbili- 

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

 the axial sculpture, which becomes a little heavier and more irregular 

 on the umbilical wall. Aperture almost circular, very slightly angu- 

 lated at the posterior angle; peristome simple; outer lip thin; inner 

 lip slightly thickened. The parietal wall is covered by a moderately 

 thick callus which is separated from the preceding turn by an 

 impressed line rendering the peritreme complete. 



U.S.N.M. No. 307401 contains two specimens, one of which has served 

 for our figure. They were collected by Cuming on Chimborazo, 

 Ecuador. The specimen figured has 4i/4 whorls and measures : Height, 

 11 mm. ; greater diameter, 22 mm. ; lesser diameter, 18.5 mm. Height 

 of aperture, 9.5 mm. ; diameter, 9.9 mm. 



This species resembles A. (A.) fasciatum (Kobelt) in having the 

 last whorl decidedly deflected but differs from it in being much paler 

 and m having the umbilicus wider. 



