SOME NEW DEVONIC FOSSILS 285 



-Ope Hall, Hamilton). The surface is crossed by fine and obscure 

 concentric lines. On the interior the ventral valve bears flabellate 

 muscle scars but it is not known whether the. scars of the dorsal 

 valve conform to those of Schizophoria. Specimens of this species 

 are easily confounded with those of Dal. 1 u c i a but the con- 

 tour of the two is exactly reversed. 



Dimensions. A normal specimen measures i8 mm in length 

 -and 20 mm in width. 



Lower Devonic. Grande Greve, P. O. 



Orthostrophia canadensis nov. 



Valves subcircular with a straight hinge; in contour the 

 ventral valve is the shallower but bears a high median ridge, while 

 the deeper dorsal valve carries a broad and low median sinus. 

 -Inside, the ventral valve has the muscular area concentrated pos- 



Orthostrophia canadensis 



teriorly into a single scar not more extensive than the single pedicle 

 scar in more typical orthids ; the dorsal valve has a thin erect car- 

 dinal process and four distinct adductor scars. 



The surface is marked by radial striae of unequal size. 



Loiver Devonic. St Alban beds. The Grande Cavee, and Cape 

 Rosier Cove. This species is also known to occur in the Square 

 X<ake limestone of Northern Maine. 



Dalmanella penouili nov. 



This is a small circular shell without median depression or de- 

 viation but with an elevated ventral valve and high cardinal area, 

 simulating in this regard a Schuchertella but without the deltidium 



