1870.] ^'^'^ [Winchell. 



Perkopecten limattjs? Will. (Proc. A. K S., P., July, I860, p. 12G.) 

 JSTewark, and bed No. 4, Seiotoville, Ohio. 



Like the other Ohio representatives of the species of this family, the 

 specimens of this species are considerably larger than the Iowa types. 



AviCtTLOPECTEH NeWARKENSIS, 11. Sp. 



Dorso-ventral and antero-posterior diameters and length of hinge line as 

 the numbers, 14, 10 and 7. Left valve rather convex, its cardinal slopes 

 forming an angle of about 60°, and thus creating a sharper beak than is 

 usual in this genus. Anterior ear somewhat inflated, with about six 

 strong radiating strife, finer intermediate ones, and numerous fine decus- 

 sating striae. Posterior ear a little smaller, flat, its posterior boundary 

 nearly at right angles with the hinge. Beak scarcely exceeding the hinge. 

 Surface marked with numerous fine, unequal, slightly wavy, delicately 

 crenulated, radial striae. 



Dorso-ventral diameter fouiteen-sixteenths of an inch ; antero-posterior, 

 ten-sixteenths ; length of hinge line, seven-sixteenths. 



The strias are of the size of those in J., tenuicostus, "Win., but they are 

 less rigid, regular and uniform ; the shell is less circular, and the umbo 

 is more prominent. 



AvicuLOFECTEN Caroli, Win. (Proc. A. N. S., Phil., Jan., 1863, p. 9.) 

 From Newark, bed No. 4, Seiotoville, and from Granville, 0hi6. 



The specimens from Licking county are all right valves, and are much 

 flatter than typical specimens of the same valve. 



AvicuLOPECTEN occiDENTALis, Win. (Proc. A. N. S., Phil., Jan., 1863, 

 p. r.) From Newark, Licking county, Ohio. The largest specimen is 

 twice the size of the Iowa types. A right valve of the same size, from 

 Granville, shows also obsolete, irregular, radiating furrows around the 

 margin of the cast . 



Sakqxjinolites naiadiformis, n. sp. 



Length Iwo and a half times the height ; laterally flattened below the 

 umbo ; dorsal and ventral margins parallel or nearly so — the ventral 

 sometimes with a broad shallow sinus extending upwards over the valves 

 and vanishing near the umbo ; a distinct umboiial ridge flattening out 

 near the postero-ventral angle, at. which i^lace the outline presents a 

 rounded angulation ; the postero-dorsal slope making, Avitli the dorsum, 

 an angle of 45°. 



Length, 2;] inches ; height, one and one-sixteenth inches ; thickness, 

 half an inch. 



The above description is based on a specimen from Hillsdale, Michigan. 

 Mr. Herzer has sent a single specimen from Newark, Ohio, which agrees 

 with this ; but such is the state of preservation of lamellibranclis iu this 

 formation, that there is extreme difficulty in ascertaining their generic 

 characters. Another specimen from Granville, Ohio, presents a still bet- 

 ter specific accordance. 



Sangtjinolites (Ctpricardia?) sectjris, n. sp. 



Outline of shell sub-oval, anteriorly indented by a small luntile, over 

 which hangs the small, incurved, approximated, sub-terminal beaks. A 

 very prominent,' sub-acute ridge runs from the beaks posteriorly and but 



