SOME NEW DEVONIC FOSSILS 211 



somewhat the aspect of unequal and flat riblets produced by series 

 of incised lines. These multiply and broaden unequally present- 

 ing* much the same aspect as those in P. edmundi of the 

 Chapman Plantation. 



The right valve is depressed ; on the posterior wing deeply con- 

 cave, convex but not elevated along the crescence line, thence slop- 

 ing to the lower margin with an incurved surface, the postlateral 

 edge of the valve being upturned. The byssal notch and sinus are 

 indicated by a marginal incurvature and depression. One speci- 

 men shows the striated ligament area, a small anterior adductor 

 and slender anterior tooth. Surface of this valve entirely smooth 

 or with concentric lines only. 



This shell is characterized by its extreme convexity and 

 incurvature. 



Lower Devonic. Dalhousie, N. B. 



Pteronitella hirundo nov. 



Shell much elongate on the hinge, terminating posteriorly in a 

 slender, acute point, anteriorly blunt, the auricle atrophied and 

 the anterior slope of the valves abrupt. Beak subterminal, ele- 

 vated, umbonal ridge subparallel with the anterior margin. From 

 this ridge the surface of the left valve slopes very gradually 



Pteronitella hirundu 



downward and back; right valve flat except at the beak. Surface 

 of left valve bearing sharp and numerous radial lines, crowded and 

 with a tendency to fasciculation over the anterior and lower parts 

 but equidistant posteriorly. The hinge and ligament areas are 

 bounded and crossed by a few very strong striae, the cardinal edge 

 of the valve being thickened. All these lines are crossed by con- 

 centric striae, short and elevated everywhere except on the posterior 

 cardinal surface. On the right valve the radial lines are obsolete 



