5O PALEONTOLOGY OF NEW JERSEY. 
below; outer lip slightly thickened periodically, broadly sinuate on the 
margin in the upper part, smooth within; volutions ventricose above and 
contracted below, longitudinally costate and spirally lined; axis not umbil- 
icated. Type P. subdensata Conrad. 
The genus is most nearly allied to Pyropsis, T udicla, and Rapa. It differs 
from each of them in the thickened, callous columella; from Rapa in want- 
ing the umbilicus; from Pyropsis in the shorter beak (want of angulations on 
the volutions in some species), and in having the inner lip entirely united 
with the columella or beak of the shell; fronr Tudicla in the shorter beak, 
smooth inner surface of the outer lip, and pyriform shape and_ posterior 
channel. From some of the Tudiclas herein described under that genus, 
there appears but slight difference except in the features of the aperture and 
columella; and in the casts it is somewhat difficult to say to which genus 
they belong. 
PYRIFUSUS ERRATICUS, N. sp. 
Plate tv, Figs. 4, 5. 
Shell of medium size, a very fine specimen used, measuring 14 inches 
in length; nearly equally fusiform or biconical in general outline as viewed 
from the back; apical angle about 50°; volutions, about four in number, 
the last one large, subangular on the periphery, concave above, rounded 
below the middle, and contracted in the lower part; upper volutions con- 
vex; suture distinct; aperture elongate; canal short; the volutions crossed 
by nine or ten vertical plications, which are strong, prominent, and 
rounded on the larger part of the volution, and but faintly marked on the 
lower convexity of the last one, becoming obsolete before reaching the 
beak; the entire surface of the shell also marked by beautifully rounded, 
spiral lines, which are alternately larger and smaller, and very closely 
arranged; these again crossed by finé transverse lines of growth, which 
make a broad and rather strong retral curve from the suture to the most 
prominent part of the longitudinal plications, below which point they again 
bend forward to the swell of the volution below; columella and axis 
unknown. 
