516 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.51. 



CERITfflUM INSULATUM, new species. 



Plate 86, fig. 12. 



Shell small, acute, strongly sculptured with more than nine rounded 

 whorls (the apex defective); suture distinct, not channeled; axial 

 sculpture of 12 to 15 rounded ribs extending from suture to suture, 

 but not over the base, with occasional much stronger but similar 

 varices irregularly distributed; spiral sculpture of (on the penul- 

 timate whorl) five rounded tlireads, subequal and equidistant, which 

 are swollen where they override the axial ribs; there is a strong 

 simple spiral cord, at the periphery of the base, which is sometimes 

 more or less visible behind the suture, and on the moderately rounded 

 base are two or tliree rather strong spirals with equal or wider inter- 

 spaces; the canal is short and twisted; the aperture concealed by 

 matrix but with a thickened outer lip. Height (slightly decollate), 

 19; height of last whorl, 6.5; maximum diameter, 9 mm. 



Locality. — Station 7075, on the east bank of Flint River, 10^ miles 

 below Bainbridge, Decatur County, Georgia, just above Lambert 

 Island; Cooke and Mansfield, 1914. U. S. Nat. Mus. Cat. No. 166739. 



Tliis species belongs to the group of Ceritliium muscarum Say, and 

 C. georgianum Sowerby, but is sufficiently distinct from either. 



CERITHIOPSIS DIAGONA, new species. 



Plate 86, fig. 7. 



Shell small, slender (decollate), with 10 remaining flat-sided whorls; 

 last whorl with a mesial constriction, on each side ol which are two 

 spiral cords, the anterior pair subequal, separated by a narrow sulcus, 

 with the most anterior forming the periphery of the whorl; both 

 cords are nodulously undulated, with about 22 nodulations separated 

 by narrower intervals; of the posterior pair the fu'st is laid upon the 

 preceding inconspicuous suture and is broader than either of the 

 anterior pair, is similarly but less distinctly undulated; the second 

 cord is much smaller but also undulated. The base is flattened and 

 nearly smooth, or faintly spirally striate, the condition of the speci- 

 men makmg the determination of the surface uncertain ; the aperture 

 is subquadrate, the canal short and twisted, the edge of the pillar 

 with a thick not very sharply defined fold. Length of specimen as 

 figured, 10; diameter of the base, 4; length axially of the last whorl, 

 2 mm. 



Locality. — Station 7074, on the west bank of the Flint River at Hale 

 landing, 7 miles southeast of Bainbridge, Decatur County, Georgia, 

 in coralhferous chert; Vaughan, Cooke, and Mansfield, 1914. U. S. 

 Nat. Mus. Cat. No. 166740. 



