GASTEROPODA OF THE LOWER GREEN MARLS. 63 
Genus SERRIFUSUS Meek. 
SERRIFUSUS ? CROSSWICKENSIS, n. sp. 
Plate v, Figs. 24, 25. 
Shell small or of medium size, biturbinate in form, shorter below than 
above the middle, exclusive of the beak, the extension of which is unknown, 
‘asts only having been observed; spire broadly conical, the apical angle 
measuring about 55°; volutions about four and a half or five on the inter- 
nal cast; angularly ventricose, vertical or concave on the periphery, the 
latter character particularly a feature of the body volution; upper side 
of the volutions obliquely sloping, the slope being somewhat greater than 
the angle of the spire, so as to reveal the vertical portion of each volution; 
lower side rounded; aperture nearly as broad as high, as seen in a transverse 
section, the outer lip slightly biangular, corresponding to the narrow vertical 
band of the periphery; columella strong, indicating a rather robust beak; 
surface features unknown. 
This species differs from S. nodocarinatus, herein described, in having a 
less elevated and broader spire; in having a vertical peripheral band, and 
in being destitute of the transverse nodes on the peripheral carina, so far as 
can be seen on the cast. There is a slight indication of a single spiral ridge 
a short distance below the central band, but it is hardly definite enough on 
the cast to be given as » positive feature, and it is also possible there may 
have been nodes on the carinations formed by the band, but there are no 
indications of such a feature remaining. Were it not for the very evident 
rostral beak, although probably very short, there might be reasons for con- 
sidering the casts those of a species of Plewrotomaria, but the existence of 
this feature would entirely remove it from that group of shells, although 
many of the Palzeozoic forms referred to that genus present a short, straight 
columella; but here there has been, I think, without question, a true rostral 
beak and canal. 
Formation and locality: In the blackish marls at the base of the Lower 
Green Sands at Crosswicks, New Jersey. Collection at Rutgers College. 
