xo. 2297. BRACHIOPOD GENUS PLATYSTROPHIA—McEWAX. 439 



Figs. 3-6. Platystrophia trentonensis. new species, p. 407. 



3. Pedicle valve. The figure shows the presence of three plications in the sinus. 



4. Pedicle valve of a long-hinged siiecimen. 

 Trenton group (Prosser limostoue) Decorah. Iowa. 



5. Brachial valve showing the bifurcation of the median i)licatioii. 



6. Anterior ^'iew. 



Trenton group (Prosser limestonei. Fountain, Minnesota. 

 Figs. 7, 8. Platystrophia precedens, new species, p. 405. 



7. Pedicle valve showing two plications in the sinus merging into one at the beak. 

 Trenton group (Curdsville limestone), Mercer County. Kentucky. 



8. Pedicle valve of a plump specimen. The presence of one plication in the sinus 



at the beak is shown. 

 Trenton limestone near Lake Champlaiu. New York. 

 Figs. 9-11. Platystrophia trentovensis champlainensis. new variety, p. 407. 



9. Pedicle valve. The biplicate plication pattern is well shown. 



10. Cardinal \'iew showing the short hinge line. 



11. Brachial valve. The figure illustrates the bifurcation of tin- median plication. 

 Trenton limestone near I^ake Champlain. New York. 



Figs. 12-14. Plati/strophia trentoneims perplana. new variety, p. 407. 



12. Pedicale valve showing the intercalation of a median plication in the sinus. 



13. Cardinal view. The thin form is typical. 



Trenton group (Curdsville limestone). Crossville Quadrangle. Tennessee. 



14. Brachial valve. The figure shows the biplicate arrangement of the plications 



of the fold. 

 Trenton group (Curdsville limestone). Mercer County. Kentucky. 

 Figs 15-19. Plati/strophia hermitagensis. new species, p. 409. 



15. Pedicle valve showing the broad shallow sinus. 



Trenton group (Hermitage limestonei. Payton's Creek. G miles northwest of 

 < 'arthage . Tennessee . 



16. Bracliial valve showing the low multiplicate fold. 



17. Pedicle valve. This specimen lacks the usual median ])lication in the sinus. 



18. Anterior view. The thin form is characteristic. 



19. ( ardinal view. The presence of two plications on the fold at the beak is shown 



in this figure. 

 Trenton group (Hermitage limestone). Auburn, Tennessee. 

 Fig. 20. Platystrophia. species. 



20. A specimen of the Biplicate Croup with two plications in the sinus. Only 



one valve was found. 

 Trenton group (Prosser limestone). *'annon Falls, Minnesota. 

 Figs. 21. 22. Platystrophia n-gularis Shaler, p. 405. 



21. Pedicle valve sho^\ing the two plications in the sinus. The outer margin haa 



been broken away. » 



22. Brachial valve partly buried in limestone. The three plications on the fold 



are typical. 

 Richmond group (Ellis Bay), Cliff, one-half mile east of Junction Cliff, Anti- 

 costi Island. 

 IiG. 23. Platystrophia reversata (Foerste). p. 408. 



23. Pedicle valve sho\ving the multiplicate sinus. .The outer edges have been 



broken awa>'. 

 Albion group (Brassfield limestone). Dayton. Ohio. 

 Fig. 24. Platystrophia daytonensis (Foerste). p. 406. 



24. Brachial valve. The three plications on the fold are typical. 

 Albion group (Brassfield limestone). Nelson County. Kentucky. 



