148 



Camerella Ops. (N. sp.) 



Fig. 128. 

 Fig. 128. — Camerella Ops. — a, Dorsal, b, side view. 



Description. — Sub-globular, transversely sub-elliptical, greatest ■width a 

 little in front of tbe middle, sides rounded, front margin undulated by the 

 coarse ribs and mesial sinus. Ventral valve very convex, strongly tumid 

 in the upper half ; umbo large, rounded ; beak incurved down beneath 

 that of the opposite valve ; mesial fold obscure, extending to the umbo 

 with a shallow, wide, obscure sulcus on each side. Dorsal valve smaller 

 than the ventral, most convex in the upper half; beak small, not incurved, 

 but depressed below the greatest elevation of the shell ; a small area 

 beneath it, inclining outwards at an obtuse angle with the plane of the 

 margin ; mesial sinus deep, rounded in the bottom, becoming obsolete at 

 about two-thirds the length of the shell, an obscure rounded fold on each 

 side. Surface with a smooth aspect, but, when closely examined, exhibiting 

 numerous fine undulating concentric striae. There are a few obscure 

 undulations, indicating ribs at the front margin. 



Locality and Formation. — The Jumpers, Anticosti. In Division 4, 

 Anticosti group ; Middle Silurian. 



Collector. — J. Richardson. 



