PAGE 



Figs. 1-3. KIXEDENELLA cLARKEi VAB. PAUPERA Ulrich and Bassler 534 



1. Left side of complete carapace showing the emaciated appearance 



and the granules in some of the furrows. 



2, 3. Ventral and anterior end views of same. 



Helderberg formation, Keyser member, Cumberland. 



Figs. 4-6. KLCEDENELLA TUKGIDA Ulrich and Bassler 535 



4. Right valve of an unusually short specimen. X 20. 



5, 6. Left and right valves of an average specimen. X 20. 



Helderberg formation, Keyser member, Cumberland. 



Fig. 7. KLCEDENELLA TUKGIDA VAR. VENTROSA Ulrich and Bassler 535 



Left valve of a complete carapace. X 20. Helderberg formation, 

 Keyser member, Cumberland. 



Fig. 8. THLIPSURA MTILTIPUNCTATA Ulrich and Bassler n. sp 536 



Lateral view of right valve. X 20. Oriskany formation, 21st Bridge. 



Figs. 9-11. OCTONARIA ? ANGULATA Ulrich and Bassler n. sp 537 



Two right and a left valve showing slight variations in outline and 

 markings. X 20. Helderberg formation, Keyser member, Cum- 

 berland. 



Figs. 12-18. OCTONARIA IN.EQUALIS Ulrich and Bassler n. sp 538 



12-14. Left side and posterior and ventral views of a complete carapace. 

 X 20. 



15. Right side of another specimen more elongate than usual, showing 



the relatively small size and different pitting of the right valve 

 as compared with the left valve. X 20. 



16. Left valve of a somewhat shorter form in which the two lower pits 



are confluent. X 20. 

 17, 18. Longitudinal and ventral sections of same. X 20. 



Helderberg formation, Keyser member, Cumberland. 



Fig. 19. OCTONARIA SIMPLEX (Krause) 538 



Left valve. X 20. Helderberg formation, Keyser member, Cumber- 

 land. 



Fig. 20. CRATERELLINA OBLONGA Ulrich and Bassler n. sp 540 



Right valve showing the crater-like anterior pit and the somewhat 

 irregular shape pertaining to this species. X 20. Oriskany 

 formation, 21st Bridge. 



Fig. 21. CRATERELLINA ROBUSTA Ulrich and Bassler n. sp 539 



A characteristic right valve of this large and well marked species. 

 X 20. Oriskany formation, 21st Bridge. 



Fig. 22. BYTHOCYPRIS PUNCTULATA VAR. ARCTATUM Ulrich and Bassler n. 



var 540 



Lateral view of left valve. X 20. Helderberg formation, Keyser 

 member, Cumberland. 



Figs. 23-25. PONTOCYPRIS ARCUATA Ulrich and Bassler n. sp 541 



23. Right side of a complete carapace. X 20. 



24, 25. Dorsal outline and posterior end view of same specimen. X 20. 



Helderberg formation, Keyser member, Cumberland. 



Figs. 26-28. PONTOCYPRIS MAWII VAR. BREVIATA Jones 541 



26. Left valve. X 20. 



27. Outline from the dorsal side. X 20. 



28. Anterior outline view, showing dorsal overlap of the right valve 



and ventral overlap of the left. 



Helderberg formation, Keyser member, Cumberland. 



Figs. 29-31. PACHYDOMELLA LONGULA Ulrich and Bassler n. sp 542 



29. Right valve. X 20. 



30. 31. Ventral and posterior end views of same. X 20. 



Helderberg formation, Keyser member, Cumberland. 



