32 PALEONTOLOGY OF NEW JEESEY. 



species, as several of them have ribs distinctly alternating in size and quite 

 unequal, with probable implantations or bifurcations, while others have 

 ribs of an even size and simple. I do not think they could well have 

 been opposite valves of the one species. The specimens are too poor and 

 meager to illustrate, but I do not think they represent P. vicenarius as above 

 described, and as the species has never been figured, there is nothing but 

 the description to guide one in determining it. The types were from Wil- 

 mington, N. C. I do not recognize these fragments as pertaining to any 

 described form, unless possibly the simple ribbed form might represent 

 P. micropleura of H. C. Lea, 1 though some of them have not had a sufficient 

 number of ribs. Or they may be related to P. tricenarius of Conrad, 2 but 

 they are too imperfect for determination. 



Genus VOLA Klein. 



VOLA HUMPHREYSI. 



PL iv, figs. 6-9. 



Pecten Humphrey sii Conrad: Proc. Nat. Institute (2d Bulletin), p. 194, PL n, fig. 2; 

 Cat. Miocene Foss., Proc. Acad. Nat Sci. Phil., Dec. 1862, p. 582; Meek, Check 

 List Smith. Inst., p. 4; Heilprin, Mioc. Moll. State of New Jersey, Proc. A. N. S. 

 Phil., 1887, p. 297 et seq.; Heilprin, Cont. Tert. Geol. & Pal. U. S., p. 8. 



Tola ffumphreysii Conrad: Cat. Mioc. Foss, Proc. A. N. S. Phil., 1862, p. 582. 



Mr. Conrad's description of this species is as follows: " Suborbicular, 

 inferior valve convex; superior flat, and with about seven remote, narrow, 

 convex ribs, and concentrically wrinkled ; towards the apex is a concave 

 depression; ears equal, sides direct and straight; inferior valve with the ribs 

 wide, approximate, plano-convex and longitudinally striated; one of the 

 ears emarginate at the base." In his observations he states that, " Of two 

 specimens in the collection of the college at Annapolis, the largest measures 

 3 inches from beak to base." 



Prof. Angelo Heilprin in a recent paper 3 proposes the varietal name 

 Woolmani for the New Jersey specimens of the species, considering them 



1 Trans. Am. Phil. Soc. Penn., vol. 9, p. 19; pi. 35, fig. 32. 



2 Miocene Foss., p. 74; PI. 42, fig. 2. 



3 Proc. Acad. Nat. Sci. Phil., 1887, p. 405. 



