193 



volutions five, rounded ; last one large and ventrirosc ; suture dis- 

 tinct, depressed ; aperture narrow, curved, pointed above, gradually 

 widening to the base ; outer lip tbickencd, broad, acute above, pro- 

 longed uj)on the spire, inner edge strongly crenulated, outer surface 

 marked with distinct, longitudinal, and transverse lines, and present- 

 ing a finely canjpellated appearance ; columellar lip thickened and 

 marked below with strong teeth. Surface with rather coarse, rounded 

 revolving lines, of which there are about sixteen on the body volu- 

 tion ; these are crossed by very fine, crowded strias of growth, which 

 give to the intervals between the revolving lines a minute punctate 

 appearance. 



Length, . 26 inch ; width, 0.20; apical angle, 60°. 



Ripley Group, Chatfield Point, Navarro County. 



B. F. Shumard and W. P. Riddell collectors. 



R. SUBPELLUCIDA, (n. sp.) Shell small, ovate, smooth, polished ; 

 spire elevated, conical ; volutions four to four and a half, gently con- 

 vex ; last one ventricose ; suture sharply impressed, linear ; aperture 

 narrow, grooved, acute above, gradually enlarging to middle and 

 thence rapidly to base ; outer lip thickened, prolonged, terminating 

 above in an acute point, which is sometimes fi*ee, inner edge neatly 

 crenulated, external margin marked with fine, longitudinal lines ; 

 columellar lip coated with a thin callus, and bearing below two promi- 

 nent flexuous folds, with a smaller one in the interval between. 

 Surface with extremely fine lines of growth, and a few revolving 

 strias at base, which are scarcely visible to the naked eye. 



Length, 0.23 inch; width, 0.15. 



Marly clay group, bluffs of Red River, Lamar County. 



G. G. Shumard and A. Roessler collectors. 



R. ACUTiSPiRA, (n. sp.) Shell small, elongate-ovate, polished, 

 length not quite double the width ; spire elevated, conical, acute at 

 tip ; volutions six and a half or seven, gently convex anH marked at 

 the upper margin with a narrow brown band ; body volution moder- 

 ately ventricose ; suture linear, distinctly defined ; aperture occupj-ing 

 about half the total length of the shell, acute above, rounded below 

 and notched by a short sinus ; outer Kp with a narrow reflected margin 

 and terminating above in a narrow produced angle ; columellar lip 

 coated with a thin limy deposit and bearing below two prominent 

 sinuate lamellar folds ; surface with extremely fine strife of growth, 

 crossed below the middle of the body volution with two distant, 

 sliglitly impressed revolving lines, and at the base with five or six 

 close striffi. 



Length, 0.26 inch ; width, 0.14; spiral angle 59°. 



This is a remarkably pretty species, and readily distinguished from 



PROCEEDINGS B. S. N U.— VOL. VIIT. 13 OCTOBEIJ, 1861. 



