Anculosaic of tiik Ai,Ar.AMA RivKR Drainage 31 



The nuclear whorls are tightly coiled, smooth and not upon the same 

 plane, the embryo shell appearing to be one and one-fourth to one and one- 

 half whorls in size. In one young and uneroded specimen the nuclear whorls 

 are bright red, smooth, elevated; the second whorl dark green, slightly 

 carinate, shining and smooth between the carinae; the third whorl angulated 

 at the base, folded, having four interrupted bands. In another juvenile the 

 second whorl has a slight beading at the top close to the suture, a spot of 

 color occuring between nodes. 



The operculum is dark red by transmitted light, about twice as long as 

 wide. Lines of growth are pronounced, the margins thickened and usually 

 smooth, the apex pointed though sometimes rounded. The polar point is at 

 the edge of the left margin below the center. The operculum is usually 

 "indented" at the polar point where the animal has rubbed the operculum 

 against the columella. In instances, the basal margin has been worn away 

 until the nucleus rests upon the base. The spiral lines in most of the op- 

 ercula examined are very nearly obsolete. Three whorls are indicated, the 

 first two very tightly coiled. Tryon illustrated a specimen of griffithiana 

 with tongue-shaped operculum, but makes no mention of it in the text. Num- 

 bers- of shells with opercula of this nature are in the Alabama collection. 

 This fonii is described elsewhere. 



A label in a tray of Wetumpka griffithiana reads : "On rocks in swift 

 water less than 4 feet deep when the river is low." 



Measurements of shells: 



Anculosa aldrichi H. H. Smith, new species 



Fig. 16 



Shell: Subglobose, smooth, shining, subangulate, the base somewhat flattened 

 and indented. Color of epidermis light brown, crossed by four dark, discontinuous 

 bands each about i mm. wide. Within the aperture these bands appear against a 

 bluish-white background of shell material. Apex eroded, the body whorl alone 

 remaining entire. Lines of growth fine, regularly spaced, interrupted by three rest- 

 period scars which are rather narrow, two of them being raised above the surface of 



