94 THE NAUTILUS. 



the white variegation; below the suture there are spaced groups 

 of slightly enlarged white striae, giving the appearance of very 

 low, protractive folds there. The first 1 whorls are smooth 

 and glossy, apex flattened; following whorls are slightly con- 

 vex; last whorl flattened, projecting in a short, rounded neck. 

 The aperture is squarish-ovate, vertical, light brown within. 

 Peristome pale brown, rather broadly expanded. The superior 

 lamella is vertical, strong but thin, concave on the left side, 

 curving to the left where it joins the spiral lamella, which pene- 

 trates scarcely deeper than the dorsal side. The inferior lamella 

 is moderately developed, becoming strong within, and penetrat- 

 ing to a mid-ventral position. The principal plica is about half 

 a whorl long, running from the middle of the right side to a 

 little past the beginning of the neck. The lunella is dorso- 

 lateral, well developed and strongly arched. 



Length 27.8, diam. at penult whorl 4.7 mm.; longest axis of 

 aperture 5.4 mm.; 12 whorls. 



Length 26.3, diam. 4.6, aperture 5 mm.; 12 whorls. 



The clausilium is bluntly pointed at the palato-distal ex- 

 tremity, slightly excised at the filament. 



Caspisapo, Rio Huallaga, Peru. Cotypes in A. N. S. P. and 

 Bryant Walker coll. 



Nenia pampasensis (Pils.) has about the figure of this species 

 but differs in sculpture among other features. 



NENIA FLACHI TINGAMARLE n. subsp. PI. 2, fig. 3. 



This form agrees in the main with N. flachi Boettger, but 

 differs by the more widely spaced striae. In N. flachi the strise 

 are crowded, 16 to 18 in one millimeter on the face of the last 

 whorl. In this race there are 8 to 9 in one millimeter. Coarse, 

 low, spiral striae are present and well developed. The color is 

 a very pale brown, somewhat translucent, the shell being quite 

 thin. 



Length 23.2, diam. at penult whorl 5.2, largest axis of aper- 

 ture 6.6 mm.; 6 whorls remain. 



Length 23.5, diam. 5.2, aperture 6.8 mm.; 6 whorls. 



Tinga Maria, Peru. Cotypes in A. N. S. and Bryant Walker 

 collections. 



