138 PALEONTOLOGY OF NEW YORK. 



Ptychuptekia Eudora, n. .•^p. 



'l.ATK LXXXV, KIG. H. 



Shei.1, <iI' iiioiliuin size. ihoiiil>i)iilal : liody narrow, elongate-ovato, oliliijiK' at an 

 angle of about •Sd'^' witli the hinge-line; length nearly twice the height; 

 ;intc-li\ ssal margin oljliqne, curving into tlic long, shallow sinus; base 

 broadly curved ; posterior end acutely recurved. 



Left valve gibbous above, convex below. Right valve unknown. 



Hinge-line straight, greater than the height of the shell. 



Beak a little in front of the anterior third of tlie liinge directed I'orward, 

 rising above the cardinal line. Undio narrow and gibl)OUs, subtending a 

 very acute angle. 



Anterior end small, limiteil l)y a wcll-markt'd and oblique Inssal depre.ssion ; 

 extremity acute. The distance from the byssal sinus to tlic cardinal margin 

 is (me-half the greatest heiglit of tlie valve. Wing joining the body one- 

 fourth its length above the posterior end; the shallow furrow and fold defin- 

 ing its limits are not strongly marked ; margin ol)li(juely tiuncate ; extremity 

 not produced. 



Test thin, marked by radii which are very fnie and imdulating on the 

 body and wing, while they are obsolete on the anterior portion; these are 

 cancellated by fine concentric stria), which on some portions are fasciculate, 

 and very conspicuous on the anterior end. 



Interior unknown. 



The specimen described has a length of ob nun., iieight lid mm., and 

 hiiiKe-line about 23 mm. 



o^ 



This species bears considerable resenddance to P. Eucrate, but its anterior end 

 is proportionally narrower, and it may also be distinguished l)y the absence of 

 a continuous angularity along the body, the Jiiore abru])t recurving of the post- 

 basal margin, the more obli([ue truncation of the wing, and the less eon.spicu- 

 ous surface markings. It diflers from P. Spio in its more gibbous umbo and 



