252 BULLETIN 181, mSTITEiD iSWATES NATTON'AL MUSEUM 



APEROSTOMA (APEROSTOMA) CASTANEUM, new species 



Pi^TE 36, Figures 7-9 



Shell low, helicoid, bright chestnut-brown on the upper turns, with 

 a light zone immediately above the periphery and a broad dark 

 chestnut-brown band immediately below the periphery. The rest 

 of the base is golden horn colored ; interior of aperture bluish white, 

 the edge buff colored. The nucleus consists of 2 small, well-rounded, 

 smooth turns. The postnuclear whorls are moderately rounded, 

 well impressed a little anterior to the suture with a slender cord at 

 the suture. The last whorl is decurrent for about one-quarter of a 

 turn. The postnuclear whorls are marked by strong, retractively 

 curved, very regular axial riblets, which become decidedly weakened 

 on the last quarter of the last whorl. Suture strongly impressed. 

 Periphery well rounded. Base moderately broadly, openly umbili- 

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

 of the axial ribs, which do not become stronger on the umbilical 

 wall. Aperture very large, very broadly ovate with a slight angu- 

 lation at the posterior angle; peristome simple; outer lip thin, 

 decidedly produced on the outer lip and slightly reflected; inner 

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

 thick callus, which renders the peritreme complete. 



The type, U.S.N.M. No. 524087, comes from Venezuela without 

 specific locality. It has 4.4; whorls and measures: Height, 18.4 

 mm. ; greater diameter, 32,2 mm. ; lesser diameter, 21.4 nun. Height 

 of aperture, 12.3 mm. ; diameter, 15.7 mm. 



This species resembles A. (A.) olivaceimh but differs from it in 

 having the axial sculpture much stronger and the last whorl de- 

 cidedly decurrent and in being of much darker coloration. 



APEROSTOMA (APEROSTOMA) PERUVIANUM (Da Costa) 



Plate 36, Figures 16-18 



1906. Neocyclotus peruvianus Da Costa, Proc. Malac. Soc. London, vol. 7, p. 98, 



pi. 11, figs. 7-9. 

 1923. Poteria {Neocyclotus) peruvianus H. B. Baker, Occ. Pap. Mus. Zool. 



Univ. Michigan, No. 137, p. 42. 



We have not seen specimens of this species and so give a translation 

 of Da Costa's description and copy his figures : 



Shell large, openly umbilicated, depressed, grayish brown with a 

 narrow yellowish band above the periphery. The base bears a broad 

 dark band. Whorls 4.5, convex, impressed at the suture, obliquely 

 rib-striated. Aperture obliquely circular; bluish white. Greater 

 diameter, 38 mm. ; lesser diameter, 29 mm. 



