130 



in the British Pal. Foss., and he makes no mention of either the concen- 

 tric stride or the fine radiating lines between the large ridges. 



Locality and Formation. — Prinsta Bay, Anticosti. In Division 3, Anti- 

 costi group ; also at the Forks of the Chatte River in Gasp^. 



Collectors. — J. Richardson, A. Murray. 



Strophomena recta. (Conrad.) 



Strophomena recta (Conrad). Proc. Acad. Nat. Sci. Philadelphia, Vol. I, p. 332, 1843. 

 Lept.s:na recta (Hall). Pal. N. Y., Vol. I, p. 113, PI. 31, B, Figs. 6, a, b. 



Fig. 108. Fig. 109. 



Fig. 108. — Strophomena recta, a, side view , b, ventral view ; c, portion of 

 face enlarged. 

 109. — S. . subtenta. Dorsal valve supposed to be of this species. 



Description. — Semielliptical, both valves nearly flat, hinge-lme equal to, 

 a Uttle greater, or a httle less than the width ; sides somewhat straight 

 for about half the length, and either parallel or slightly converging for- 

 wards ; all the front half of the sheU uniformly rounded, sometimes only 

 gently convex or somewhat straight in the middle of the front margin. 

 Ventral valve shghtly convex in the umbouial region, and elsewhere flat 

 or gently concave ; beak scarcely distmct from the carduial area, shghtly 

 depressed below the umbo ; area of medium size, flat, extenduig the whole 

 length of the shell, forming an obtuse angle of from 110" to 135*^ with 

 the plane of the lateral margin ; foramen . triangular, width at the base 

 greater than the height, closed by a convex dcltidium which does not quite 

 reach the hinge-line, but has its lower margin concave. Dorsal valve uni- 

 formly very depressed convex or nearly flat, shghtly concave at the car- 

 dinal angles and with a barely perceptil)le mesial dei)ression along the 

 middle, which commences very near the beak and extends one third or 

 one half the length of the shell ; beak veiy small and minutely elevated 



