GASTEROPODA OF THE LOWER GREEN MARLS. 133 
cies when placed together being very distinct. It is very closely related 
to A. paludineformis, Natica paludineformis, TH. & M., having a much greater 
resemblance to it than the one herein described as A. Meekana, although 
that one has been commonly identified with it. This has probably arisen 
partially from the fact that this one, having originally been described 
under the name Phasianella, was so far removed systematically from the 
Naticidee, to which it really belongs, that it would scarcely be thought 
necessary to compare them, or even occur to one to do so. 
Formation and locality: In the lower layers of the Lower Green Marls, 
at Mullica Hill, New Jersey. Collection Acad. Nat. Sci., Phila. 
TROCHID 2. 
Genus MARGARITA Leach. 
MARGARITA ABYSSINA. 
Plate xvu, Figs. 1-5. 
Solarium abyssina Gabb: Proc. Acad. Nat. Sci., Phila., 1860, p. 94, Pl. m1, Fig. 9. 
Architectonica abyssina Gabb: Synopsis, pp. 39, 80. 
Margarita abyssina (Gabb) Meek: Check List Cret. and Jur. Foss., p. 18; Geol. 
N. J., Newark, p. 728. 
Shell small, not exceeding half an inch in its greatest diameter; spire 
moderately elevated, the apical angle being about 70° or 75°; volutions 
four to four and a half, very ventricose, giving a circular section when 
broken across; suture deep and well marked, while the whorls in the inter- 
nal cast are closely appressed and slightly imbedded into each other, show- 
ing the shell to be thin; also seen where the cast rests partially in the 
matrix, the space left by the removal of the shell where no compression 
has-occurred being barely perceptible; umbilicus broad and open, showing 
several of the volutions within; surface marked by very fine, even, spiral 
lines over the entire shell, with an apparent stronger line on the periphery, 
and crossed by finer lines of growth which are bent backward in crossing 
the volution, cancellating the surface. 
In Mr. Gabb’s original description the surface structure was not given, 
as he had not been able to find more than the internal cast, but among the 
