PLATE IX. 



GoNiOPiiORA MEDiocRis (page 187). 



Figure 1. Right valve. 



Grammysia remota (page 139). 



Figure 2, Right valve. 



Grammysia rustic a (page 139). 



Figure 3. Right valve, 



Grammysia acadica (fage 140). 



Figure 4. Left valve of a large specimen. 

 " 4^7, Right valve of a smaller specimen. 



Pteronitella venl'sta (page 142). 



Figure 5, A very large specimen. 

 " 5a. A smaller specimen, 

 " bb. Hinge-lin«. 



Pteroxitella curta (page 143). 



Figure G, A specimen of the average size. 



Pteronitella oblong a (page 143). 



Figure 7. A specimen of the average size. 



