PLATE LI 



PAGE 



Figs. 1-3. PRODUCTELLA LACHRYMOSA (Conrad) 564 



1. Small cast of ventral valve. 



2. Ventral valve. 



3. Sculpture cast of ventral valve. 



Jennings formation, Chemung member, top of Polish Moun- 

 tain. 



Figs. 4-9. PRQDUCTELLA LACHRYMOSA VAR. MARYLAXDICA n. var 565 



4. A large ventral valve which differs somewhat from the remaining 



specimens. Williams Road, Polish Mountain, 2042. 



5. 6. Interiors of dorsal valves. 



7-9. Ventral valves showing sparsely spinulose surface. Polish Moun- 

 tain. 

 Jennings formation, Chemung member. 



Figs. 10-12. PRODUCTELLA LACHRYMOSA (Conrad) var 565 



10, 11. Ventral valves. 



12. Portion of surface of valve shown in fig. 10, enlarged X 5. 



Jennings formation, Chemung member, 3% miles south of 

 Oakland. 



Figs. 13-15. PRODUCTELLA SPECIOSA Hall 566 



13. Ventral valve. Hancock-Harrisonville Road, 2 miles north of Han- 



cock, 1213. 



14. Ventral valve showing spinules. Woodmont, 1067. 



15. Dorsal valve. National Road, east of Millstone, 795. 



Jennings formation, Woodmont member, Ithaca fauna. 



Figs. 16-19. PRODUCTELLA HYSTRICULA (Hall) 567 



16, 17. Dorsal valves. 



18. Ventral valve. 



19. Ventral valve showing spinules. 



Chemung formation, New York. 



Fig. 20. PRODUCTELLA NAVICELLIFORMIS n. sp 567 



Ventral valve of type. Jennings formation, Parkhead member, Town 

 Creek, 2228. 



Figs. 21-23. PRODUCTUS (MARGINIFERA ?) HALLANUS Walcott 568 



21, 22. Ventral and dorsal views of a typical specimen from the Upper 



Devonian of Lime Creek, Iowa. X 2. 



23. External cast of the dorsal valves showing the lamellose, spineless 

 surface. 



Jennings formation, Chemung member, Green Glade Run, 

 near Deer Park. 



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