GASTEROPODA OF THE LOWER GREEN MARLS. 19 
as to the true generic relations of the shell. Mr. Gabb describes several 
similar forms as species of Neptunea, but none of the more recent fossil 
forms which I have examined, nor of those now living, has the broad sinus 
in the outer lip seen on this one, nor has any as straight a canal or ante- 
rior beak, while most of them are more or less marked by spiral lines. For 
these reasons I have preferred to class the present species under Gray’s 
genus Huthria, which appears to answer more nearly to its character. 
Formation and locality: In the dark-colored, fine, micaceous clays below 
the Lower Green Marls at Haddonfield, New Jersey. Collection Acad. 
Nat. Sci., Phila. 
Genus TRITONIDEA Swainson. 
TRITONIDEA OBESA, 0. Sp. 
Plate rx, Figs. 1-3. 
Shell small, short and very ventricose, the entire length being only 
about one-sixth greater than the diameter of the last volution, measured 
across the aperture; spire low, the apical angle being as great as 80°; 
body yolution inflated, very rapidly contracted below, forming a short, 
twisted canal; columellar lip somewhat thickened; aperture ovate, widest 
below the middle, contracted at the base, and somewhat pointed at the 
upper angle; volutions three and a half or four in number, and marked by 
very distinct vertical folds, which are quite numerous, closely arranged, 
but conspicuous only on the swell of the volution, becoming obsolete just 
below, where they appear to have been strongly directed forward. There 
appear to have been strong, distant, spiral ridges on the body volutions, 
numbering not more than seven or eight in all on the larger part of the 
body volution as seen on a fragment of shell preserved on one of the 
specimens. The specimens do not appear to have much exceeded five- 
eighths of an inch in length, and the substance has been very thick. 
The species is remarkable for its short, compact, and very ventricose 
form, and although not much more than internal casts, I see no reason to 
doubt their being properly referable to Tritonzdea. 
Formation and locality: In the dark green marls of the Lower Bed at 
Mullica Hill, New Jersey. Collection at Rutgers College. 
