EXPLANATION OF PLATE XXX. 



PERRISONOTA PROTEXTA Conrad, ...................................... p. 379 



1-2. Views of two internal casts of left valves, showing the 

 impression of the hinge. 



Red Bank sand; Shrewsbury River, (119). 



YOLDIA CLIFF WOODEN SIS n. Sp., ....................................... p. 383 



3. The internal cast of a left valve, imperfect posteriorly. 



Cliff wood clay; Cliff wood Point, {185). 



4. The internal cast of a right valve. 



Cliff wood clay; near Matawan, (107). 



YOLDIA LONGIFRONS (Conrad), ...................................... p. 381 



5. A very perfect internal cast of a left valve, showing the 



impression of the hinge. 



Woodbury clay; Lorillard, (102). 



YOLDIA PAPYRIA (Conrad) , .......................................... p. 382 



6. View of an internal cast of a right valve, showing the 



impression of the hinge. 



Woodbury clay; near Matawan, (/oj). 



NEMODON CONRADI Johnson, ......................................... p. 387 



7. The internal cast of a right valve. 



Woodbury clay; Lorillard, (102). 



NEMODON EUFAULENSIS (Gabb) , .......... ........................... p. 385 



8. The internal cast of a right valve. 



Merchantville clay-marl; near Jamesburg, (139). 



9. The internal cast of a left valve. 



Red Bank sand; Red Bank, (116). 



10. The internal cast of a left valve. The specimen illustrated 

 by Whitfield. 



Navesink marl. 

 n. A small form doubtfully referred to this species. 



Vinccntown formation; near Farmingdale, 



NEMODON BREVIFRONS Conrad, ....................................... P- 



12. A very perfect internal cast of the right valve. 



Cliffwood clay; Cliffwood Point, (105). 



13. The internal cast of a right valve. 



Wenonah sand; near Marlboro, (rjo). 



14. The internal cast of a large left valve referred doubtfully 



to this species. 



Wenonah sand; near Crawfords Corner, 



NEMODON ANGULATUM (Gabb), ..................................... P- 



15. The left side of the type specimen. (After Whitfield.) 

 Navesink marl? 



941. 



