130 



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

 tric strise 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 Gaspe*. 



Collectors. J. Richardson, A. Murray. 



STROPHOMENA RECTA. (Conrad.) 



STROPHOMENA RECTA (Conrad). Proc. JLcad. Nat. Sci. Philadelphia, Vol. I, p. 332, 1843. 

 LBPT2ENA RECTA (Hall). Pal. N. Y., Vol. I, p. 113, PI. 31, B, Pigs. 6, a, 6. 



Fig. 108. Fig. 109. 



Fig. 108. Strophomena recta, a, side view , &, 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-line equal to, 

 a little greater, or a little 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 shell uniformly rounded, sometimes only 

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

 Ventral valve slightly convex in the umbonial region, and elsewhere flat 

 or gently concave ; beak scarcely distinct from the cardinal area, slightly 

 depressed below the umbo ; area of medium size, flat, extending 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 deltidium which does not quite 

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

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

 dinal angles and with a barely perceptible mesial depression along the 

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

 one half the longth of the shell ; beak very small and minutely elevated 



