24 PROCEEDINGS OF THE ACADEMY OF [Feb., 



Protoconch. — Protoconch rather small, smooth, thrice-coiled, the 

 component whorls increasingly rapidly in diameter, altitude, and 

 degree of inflation. Dividing line between conch and protoconch 

 indicated by the abrupt initiation of the axial sculpture. 



Sculpture. — -Whorls of conch latticed. Axial sculpture of nar- 

 row, rounded, elevated ribs, irregularly spaced and, on the ultimar 

 and penultimar whorls, varying from 16 to 26 in number; costals 

 of spire continuous from suture to suture, strongly retractive 

 on the shoulder, weakening perceptibly posteriorly; on the ultima, 

 persisting with diminishing strength well down on to the pillar; 

 incrementals well developed. Spiral sculpture often more promi- 

 nent than the axial; lirations flat topped, well elevated threads, 

 separated by interspaces a little wider than the lirae and just 

 about equal to the intercostal areas; the spirals overiding the 

 costse at their intersection, producing a series of elevations which 

 would appear granular in a more closely sculptured shell; normal 

 number of primaries on the sides of the whorls of the spire, 3; 

 on the body and pillar, 8 to 10; anterior primary of each volution 

 following the peripheral angle; angle rounded off on the final half 

 turn and, at the aperture, almost or altogether obsolete; a single 

 secondary occurring midway between the periphery and the suture; 

 other secondaries intercalated upon the body whorl; anterior 

 fasciole threaded with 3 or 4 subequal, closely spaced lirae. 



Aperture. — Aperture rather narrow for the group, oblique. Outer 

 lip arcuate, Urate within; lirae approximately 9 in number, corre- 

 sponding in position to the secondaries on the body whorl. Col- 

 umella quite strongly excavated at the base of the body. Parietal 

 wash not sufficiently heavy to conceal the basal sculpture. Pillar 

 quite long and straight. Columellar plications narrow, oblique, 

 sub-parallel and almost equally spaced, increasing rapidly in 

 prominence from the anterior to the posterior; anterior fold mar- 

 ginal. 



Umbilicus. — An umbilical chink usually open,, though occasion- 

 ally concealed by callous. 



Dimensions. — Altitude, 29.62 mm. Maximum diameter, 17.0 mm. 



Type Locality. — 5 miles northeast of Smithfield, James River, 

 Isle of Wight County, Virginia. Yorktown Formation. 



Observations. — Cancellaria tabulata is separated from the later 

 but closely allied Cancellaria conradiana Dall by the lower spire, 

 the stouter body whorl, the much wider, much more sharply defined 

 shoulder, and the more loosely reticulated sculpture. 



