EXPLANATION OF PLATE XXXVII. 



Figs. 1— i. Group of Beyrichia tuberculata. 



1. Four views of a left valve of Beyrichia tuberculata. 



2. Similar views of a right valve of female individual of same. 



3. Four views of a right valve of B. tuberculata bigibbosa Renter. 



4. Similar views of a right valve of B. noetlingi Renter. All the figures 



are magnified five times and copied from Reuter. 

 5-10. Group of Beyrichia klcedeni. 



5. Two views of a left valve of Beyrichia maccoyiana sulcata Reuter, 



X 8. 



6. Similar views of left valve of female individual of same, X 8. 



7. Left valve of Beyrichia lindstromi Kiesow, X 8. 



Figs. 5 and 6 are copied from Reuter and tig. 7 from Kiesow. 



8. Left and right valves of Beyrichia moodeyi, new species, X 10. 

 Cayuga formation, Cacapon, Maryland. 



9, 10. Right aud left valves of Beyrichia icaldronensis, new species. X 10. 



Niagara (Waldron), Waldron, Indiana. 

 11-13. Group of Beyrichia buchiana. 



11. Left valve of Beyrichia buchiana Jones, X 8. Copied from Jones. 



12. Four views of a right valve of Beyrichia buchiana angustata Reuter. 



X 6. (After Reuter.) 



13. A right valve of Beyrichia lauensis Kiesow. (After Kiesow.) 

 14,15. Group of Beyrichia salteriana. 



14. Lateral and ventral views of a right valve of Beyrichia salteriana 



Jones, X 10. (After Reuter.) 



15. Right valve of Beyrichia granulosa Hall. (After Hall.) 

 1<>. 1 7. Group of Beyrichia clavata. 



1G. Right valve of Beyrichia clavata Kolmodin. (After Kiesow.) 

 17. Right valve of Beyrichia jonesii Boll. (After Kiesow.) 

 32G 



