NATURAL SCIENCES OP PHILADELPHIA. 287 



tudinally ribbed ; ribs rounded, prominent, curved on the last whorl ; revol- 

 ving lines close and distinct ; right lip striated within ; fold at base of colu- 

 mella distinct. 

 Locality. 



BTJLLIA, Gray. 

 Subgenus Btjlliopsis, Conrad. 



1. B. ovata. Smooth; last whorl subquadrate ; ovate or oblong-ovate, 

 entire ; whorls 5 or 6, slightly convex ; spire conical, about half the length of 

 the shell ; aperture elliptical. 



Locality. St. Mary's Co., Md. 



Shorter and broader than the other two species of Maryland, the callus not 

 prominent nor extending beyond the upper extremity of aperture. 



2. B. Marylandic a. Oblong-ovate, entire ; whorls 6, slightly convex 

 or subtruncated laterally ; suture impressed ; aperture about half the length 

 of the shell ; columella profoundly callous above, the callus extending beyond 

 the lip. 



Locality. St. Mary's Co., Md. 



Proportionally longer than the preceding, and the spire subscalariform. 

 The shell is variable in outline, the spire being much longer in some speci- 

 mens than others of equal breadth. 



3. B. quadratic, Journ. A. N. S. vi. 226. 



There are no known living representatives of this subgenus. 



COL UMBELLINsE. 



AMYCLA, H. and A. Adams. 



Subgenus Astyeis, H. and A. Adams. 



1. Amycla communis. Ovate, whorls 6 or 7, smooth and polished ; 

 spire rather elevated ; body whorl abruptly rounded in the middle or sub- 

 angular ; submargin of labrum minutely dentate. 



Locality. St. Mary's River, Md. 



A common species in the blue clay of Maryland and Virginia. 



2. A. a vara, var. granulifera. Narrow-acuminate ; longitudinally 

 ribbed ; ribs numerous, angular ; spire subturriculate ; whorls 8, crossed by 

 impressed lines, four in number, on 4 whorls of the spire, and covering the 

 body whorl to the base ; where the lines cross the ribs there is a small tubercle ; 

 labrum 7-dentate within ; columella subplicated from base to submedial angle. 



Locality. Occurs with the preceding. 



3. A. r e t i c u 1 a t a. Subturrited ; volutions 6 7, slightly convex ; lines 

 prominent, revolving and transverse lines equal in size, transverse lines most 

 remote, lines smaller and closer below the middle of last whorl ; right lip 

 toothed within. 



Locality. Virginia. 



OLIVINJE. 



DACTYLUS, Klein. 

 Subgenus Strephona, Browne. 



Dactylus e bore us. Slightly tumid on the upper part of body whorl; 

 whorls 6 in number, the penultimate contracted below the suture ; columella 

 slightly tumid, with numerous acute plaits, and five oblique plaits at base, 

 four of them elongated. 



Locality. Virginia. 



1862.] 



