10 

 O 



R. Anticostiensis, B., op. cit., p. 142. — Charleton Point and English 

 Head; H. R. 



R ? RECURViROSTRA, Hall. — This species or one closely allied to it 

 occurs abundantly in numerous localities ; H. R. 



Genus Athyris, McCoy. 



A ? ANTicosTiENSis, B., op. cit., p. 147. — Abundant near English 

 Head ; H. R. 



LAMELLIBRANCHIATA. 



Genus Cyrtodonta, Billings. 



The internal characters of the following species, have not been ascer- 

 tained, and they are, therefore, classified provisionally as belovr. I doubt 

 that any of them belong to the genus. 



C ? Harrietta, B., op. cit., p. 149. — English Head ; H. R. 



C ? Emma, B., op. cit., p. 150.— English Head ; H. R. 



Fig. 1. 



Fig 1. — Cyrtodonta? sigmoidea. a, left valve ; b, dorsal view. 



C ? sigmoidea, B. Can. Nat. Geol. vol. iii, p. 438. — Obliquely sub- 

 rhomboidal, strongly ventricose. Anterior extremity short, rounded, 

 scarcely projecting in front of the beaks ; ventral margin broadly convex, 

 the whole length ; posterior portion of the shell tapering to a rounded 

 angle situated at about half the height ; hinge line scarcely half the whole 

 length, sloping upwards and backwards ; a little more than the posterior 

 half of the dorsal margin nearly straight and sloping down to the posterior 

 angle. The beaks are small, closely incurved and usually in contact or 

 nearly so. A strong rounded convexity commences at the beaks and 

 passing along the upper side of the umbones, runs with a sigmoid curve 

 backwards and downwards. Length usually 18 hnes ; height twelve lines ; 

 depth of both valves 12 lines. Specimens two inches in length occur. 

 This species has nearly the same form as C. Smdi, but is shorter in proper- 



