126 AMERICAN JOURNAL 



ANCULOSA, Say. 



1. Plicate SjJecies. 



2. A. plicata, Con. Figs. 1 — 4. Suboval, moderately 

 thick ; spire short-conical, suture moderately impressed ; body 

 whorl slightly convex, with revolving ribs around the upper 

 part, more or less interrupted by, or altogether separated into 

 crenulations ; aperture rounded elliptical. Green, with or 

 without bands. Term. River, N. Ala. 



Fig. 4 represents tuberculatum Lea, Black Warrior River, Ala. 



2. Sulcate Species. 



8. A. Showalterii, Lea. Fig. 5. Suborbicular, thick; 

 spire scarcely raised, suture well impressed ; body whorl in- 

 flated, encircled throughout by several heavy revolving ribs, 

 causing corresponding grooves within the aperture ; aperture 

 large, suboval, the lip crenulate. Very dark brown. Coosa 

 River, A la. 



4. A. canalifera, Anth. Figs. 6, 7. Ovate, thin; spire 

 conical, suture slightly impressed ; whorls 5, the last large, 

 inflated, with several carinate revolving lines ; aperture large, 

 oval. Brown or olive. Han River, N. C. 

 Is possibly the young of A. corpulerita, Anth. 



6. A, COStata, Anth. Figs. 8, 9. Subglobose, thin; spire 

 small, short conic ; body whorl ventricose, with three to five 

 narrow equidistant revolving costas; aperture subrotund. Oli- 

 vaceous, white or purplish within. Ohio River. 



7. A. rubiginosa,, Lea. Figs. 10 — 18. Ovately gibbous, 

 thick, smooth, or more or less covered with revolving ridges 

 or stria? ; spire obtusely elevated, suture slightly impressed ; 

 body whorl somewhat constricted above ; aperture small, with 

 a heavy deposit of nacre on the labium. Greenish or reddish, 

 banded, generally purple within. Black Warrior and Coosa 

 Rivers, Ala. 



8. A. dissimilis, Say. Figs. 19 — 56. Ovate conic, thin ! 

 whorls 3 or 4, with a slight suture; body whorl large, sub- 

 carinate in the middle, and occasionally with revolving carinas 

 above or below it ; aperture broad iy ovate, sometimes with a 

 tooth upon the columella. Yellowish or greenish, not banded, 

 white within. Susquehanna River, Perm., New York, Mary- 

 land, Virginia from James River to Shenandoah River. 



A very abundant and variable species ; separated from Anculosa as a sub- 

 genus Nitocriz by H. and A. Adams, and as Mudalia by Haldeman, but it 

 does not appear to possess any permanent distinctive characters. Figs. 19 

 — 28 represent young and old specimens of the typical shell, with the carina? 

 more or less developed. Fig. 29 is a copy of the figure of DeKay's A. cart- 

 nata from Lake Champlain. Figs. 30 — 32 are transitional to figs. 33 — 3(5, 

 representing enrinata, Lea, a form inhabiting sparingly the Potomac River 



