50 PALEONTOLOGY OF NEW JERSEY. 



are sti'ong varices of growth. On the interior of" the shell the outside de- 

 pressions are represented by strong flattened ribs with angular margins and 

 deep grooves between 



It is somewhat remarkable that in all the more recent collections no 

 good specimen ot" this shell has been discovered, or any cast representing 

 it found at any other locality. 



Formation and locality. — Dr. Morton states that the fragment was found 

 near Arneytown, N. J., by Mr. Conrad. I have more recently seen other 

 fragments among specimens labeled Vincentown, N. J., which, if correct, 

 would probably place it in the Middle Marl Bed. 



Pecteu (Syncyclonema?) perlamellosiis. 



Plate VII, Fig. 7. 



Pccten perlamellom on label iu collection of tlie A. N. Sci., Pbil., apparently in Mr. 

 Conrad's handwriting. 



Shell small, broadly subcircular, with moderate!}^ convex valves. Hinge- 

 line comparatively long and the auriculations large, particularly the poste- 

 rior one, which extends more than two- thirds the depth of the cardinal 

 slope; both ears distinctly separated from the body of the shell along the 

 cardinal slope, which is sharply and abruptly elevated above their surfaces. 

 Beaks small and pointed, and the cardinal slope diverging at about a right 

 angle to each other. Posterior ear very slightly sinuated or contracted in 

 the lower part, and the anterior one nearly direct on the margin. Surface 

 of the right valve marked by distant, strongly and sharply elevated con- 

 centric lamellse, the spaces between being flat and ma iked by very fine 

 radiating hues, perceptible only by the aid of a glass. The concentric, 

 raised lamella also pass upward and cross the auriculations in nearly full 

 strengtli. Left valve unknown. Hinge characters not observed. 



It is barely possible that these shells, two of which are before me, may 

 be the young of C. BurUngtonensis Gabb, as they have about the sam'; 

 relative proportions and form as that species, but I think it highly improb- 

 able from their adult appearance and the strong distant lamellae of the sur- 

 face, which, if continued and increased in strength relatively until the shells 



