PLATE XT. 



Figure 1. Beyrichia tubercvldtn (K.\oeden), \Sir. Hrirtif>piralis,noy. Right valve 



(caHt). Magn. 7 diam. Arisaiyj, N. S. 

 '' 2. The same, var. puKlvlom, Hall. Right valve (cast). Magn. 7 diam. 



Arisaig. 

 " 3. The same- Type. Right valve icast). Magn. 7 diam. Arisaig. 

 " 4. The same, var. Noellirigi, Renter, a, rij^ht valve (cast); b, ventral 



aspect. Magn- 7 diam. Arisaig. 

 *' 5. The same, var. Noetlingi, Renter. Right valve (cast). Magn. 7 



diam. Arisaig. 

 '' 6. Beyrirhia xquilutera, Hall. Left valve (cast). Magn. 7 diam. Arisaicr, 

 '' 7. Btyrichia davigera, sp. nov. Left valve. Magn. 7 diam. Aylmer, 



Quebea 

 " 8. The same, var c/airi/rada, nov. Right valve. Magn. 7 diam. Aylmer, 



Quebec. 

 *' 9. Beyrichia qvuidrifida, sp. nov. a, left valve ; b, ventral aspect. Magn. 



15 diam. Lorette Falls. 

 " 10. Frimitiopm punciulifera (Hall). Young individual. Right valve. 



Magn. 30 diam. Thedford. 

 " 11. The same. Young individual, a, inside of left valve; Magn . 20 



diam.; b, the inner aspect of the dorsal edge; Magn. 40 



diam. Thedford, Ont. 

 " 12. Kirkhya f Walcotti, Jones, a, partly imbedded valve ; Magn. 30 



diam.; b, portion ; Magn. 60 diam. Thedford. 

 " 13. Ulrichia Conradi, J ones. Left valve. Magn. 30 diam. Thedford. 

 " 14. Primitia scitula, sp. nov. a, right valve ; b, ventral view. Magn. 20 



diam. Hay River. 

 " 15. Aparchites mitis, sp. nov. a, left valve ; b, ventral view. Magn. 30 



diam. Hay River. 

 ** 16. Isochilina hellvla, sp. nov. a, left valve ; b, ventral view. Magn. 30 



diam. Hay River. 



