GASTEROPODA OF THE LOWER GREEN MARLS. 79 



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 Euthria, 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. 



Tkitonidea obesa, n. sp. 



Plate IX, 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 volution 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 be©n 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 Tritonidea. 



Formation and locality: In the dark green marls of the Lower Bed at 

 MuUica Hill, New Jersey. Collection at Rutgers College. 



