266 DRYM^EUS, SOUTH AMERICAN. 



paneled, columella concave, with the margin reflexed and adnate 

 above. 



Alt. 23, diam. 11, alt. of aperture 10 mill.; sometimes larger, alt. 

 28 mill. 



Monte Christi, Colombia (Ginning, for typical cactivorus) ; Guay- 

 aquil and prov. Loja [Loxa], Ecuador (Wolf) ; Tumbez, Peru 

 (Cuming). 



Bulinus caclivorus BROD., P. Z. S., 1832, p. 31. SOWB., Conch. 

 Illustr., f. 2*. Bulimus cactivorus DESK, in Lam., An. s. Vert., viii, 

 p. 270. PFR., Monogr., ii, p. 175. MOUSSON, Malak., Bl., xvi, p. 

 176. B. nitidus REEVE, f. 103a. Mormus cactivorus COUSIN, Bull. 

 Soc. Zool. Fr., xii, p. 229. 



Bulinus nitidus BROD., P. Z. S., 1832, p. 31. SOWB., Conch. Il- 

 lustr., f. 2. Bulimus nitidus PFR., Monogr., ii, p. 176 ; viii, p. 153. 

 REEVE, Conch. Icon., pi. 18, f. 103b. DOHRN, Jahrb., vii, p. 89. 

 Bulimulus nitidulus BECK, Index Moll., p. 67. Mormus occiden- 

 talis MILLER, Malak. Bl. (n. F.), i, p. 121, pi. 13, f. 2. COUSIN, 

 Bull. Soc. Zool. France, xii, 1887, p. 230. 



Common along the coast from Tumbez, Peru, to Monte Christi, 

 Colombia. The passage from the whitish to the streaked forms 

 seems to be a gradual one, but it is to the latter that the names 

 nitidus, nitidulus and occidentaUs have been applied. The irregular 

 striation, very coarse for so thin a shell, almost wholly closed um- 

 bilical chink and dark apex are moderately constant characters 

 throughout the species. PI. 50, figs. 81, 82, are occidentalis of 

 Miller. 



D. DECOLORATUS (Sowerby). PI. 45, fig. 30. 



Shell oblong, subacuminate, whitish, very thin ; whorls 5 or 6, 

 longitudinally striated, a little inflated, with some interrupted 

 brownish girdles ; aperture oval, the margin acute, umbilicus small. 

 Length 0'5, diam. 0'25 inch (Sowb). 



Shell openly perforate, ovate-acute, striatulate, whitish, streaked 

 with corneous and bifasciate at base ; whorls 6, a little convex, the 

 last a little shorter than the spire ; columella subvertical. Aperture 

 oval; peristome simple, acute, the columellar margin dilated, over- 

 hanging, reflexed at the perforation. Alt. 13, diam. 6 ; alt. of aper- 

 ture 6 mill. (P/r.). 



Hills around Lima, Peru, buried in the earth under bushes (Cum- 

 ing). 



