6g PALEONTOLOGY OF STEW JEESEY. 



directed more nearly in the line of the longitudinal axis of the shell. How 

 far these features might prove constant among a larger number of speci- 

 mens I can not say; they appear to exist among the few specimens I have 

 in hand. Were it not for the surface features of the types I should have 

 been inclined to consider all the others as only varieties of V. mercenaria, 

 as I see on them no other features by which they could possibly be dis- 

 tinguished; the surface as shown on the type, however, is very distinctive. 

 Localities: Mr. Conrad gives the locality of his specimens as " Cum- 

 berland County, N. J." Those which I have in hand are from Jericho, and 

 near Shiloh, in the same county, and belong to the collection of the 

 National Museum at Washington, D. C. 



Genus MERCENARIA Schumacher. 



Mercenaria cancellata. 

 Plate xii, figs. 2 and 3. 



Mercenaria cancellata Gabb; Jour. Acad. ^at. Sci. Phil., 2d series, vol. 4, p. 376, PI. 



lxvii, fig. 25; Meek Check List, Smith. Inst., p. 9. 

 M. (Venus) 'cancellata (Gabb) Conrad: Acad. Nat. Sci., Phil., 1862, p. 574; Heilprin, 



Tert. Geol. U. S., p. 8; Proc. Acad. Nat. Sci., 1887, pp. 397, 398, and 403. 

 Compare V. capax Conrad : Miocene Foss., p. 68, PI. xxxix, fig. 4, (by error PI. xxxviii). 



" Convex beaks inclined anteriorly; umbones prominent and rounded; 

 cardinal margin slightly curved, anterior extremity and basal margin 

 rounded, posterior extremity subangular at its junction, both with the basal 

 and cardinal margin; surface marked by numerous small angular ribs 

 crossed by fine, radiating, impressed lines; anterior muscular impression 

 semilunar, posterior larger and irregular; pallial sinus small and angular." 



(Gabb.) 



The specimen from which the above description was taken is quite 

 imperfect, but enough of it remains "to show that it is distinct from any of 

 the species of the genus known to our coast, or as fossils in the Miocene or 

 later beds. A little more than half of the surface retains its natural fea- 

 tures; the rest has the outer parts removed and the inner layers consider- 

 ably weathered, while the interior is in very fair condition, except the 

 hinge, the cardinal and posterior portions of which have been quite destroyed. 



