MIOCENE MOLLUSC A AND CRUSTACEA. ' 51 



1 have not been able to compare tiiese New Jersey specimens witli 

 authentic specimens of Nnci(hi <ili/i(jii(( of Say, so can not say positively 

 wherein it differs. The tigures given by Mr. Conrad of that species would 

 answer ecjualh' well for many of the larger indi%'iduuls of this one, and I 

 presume it may be from those tigures that Mi-. Heiljirin made the identifica- 

 tion cited above. Mr. Com-ad remarks under his descri])tion of X ohliqna, 

 in liis Miocene Fossils, p. 57, that it may he a vaiiety of the i-ecent N.prox- 

 ima, which, judging from his figures, I should think more than probable. 



Localities : It occurs in fair numbers at Shiloh, Jericho, and near Bridge- 

 ton, N. J. 



Genus YOLDIA Moller. 



YOLDIA LIMATULA. 



Plate VII, figs. 11 and 12. 



¥iKuln limatula Say: Am. Conch., PI. xii; Tuoiuey and Holmes Plfocene Foss. S. Car., 

 p. 52, PI. XVII, Fig. 3; Conrad, Mioc. Foss., p. 57, PL XXX, flg. 1. 



f Nucula Icevis Say: Jour. Acad. Xat. Sci., 1st ser., vol. 4. p. 141, PI. x, flg. 5. 



f Yoldia Iwvis (Say) Courad: Proc. Acad. Nat. Sci., Pbil., 1862, p. 5S1; Meek, Check 

 List Miocene Foss., p. 5. 



YoMJa Zj»j«i(«^rt (Say's sp.) Heilpriu, Tert. Geol. U. S., ]>. 8; I'roc. Acad. Nat. Sci. 

 Phil., 1887, pp. 397, 398, and 402. 



Th'e specimens of Yoldia which are found in the Miocene mads of New 

 Jersey present to me too manv similarities and too few variations from the 

 living species, Y. linnititJa of Say, to be considered as specifically distinct, 

 or even as a variety. I have not seen any specimens of it winch present 

 quite the features of the hinge line shown in Mr. S;i3''s figures of Nucula 

 Icevis,^ from anv of the Amexicau localities, the pectination always termi- 

 nating nnich earlier tliaii there represented. Still that may be an eiTor of 

 Say's illustration only, and as the feature is not mentioned in his descrip- 

 tion, it imist remain in uncertainty. The only differences which I can find 

 between the New Jersey fossil specimens and the recent ones of the same 

 size, from along the coast near New Jersey, are, that in the fossil form the 

 valves are perhaps a little more conves; a trifle more slender posteriorly 

 and a very little more recurved than in the living ones. These I do not 

 ! Vol. 4, Ist series of the Jour. Acad; Nat. Sci. Phil, 



