THE DEVONIAN FOSSILS OF CANADA, WEST. 34) 
This species. has. all the characters of 8. inequistriata, the only 
difference being that the surface is marked by numerous concentric 
wrinkles. I retain the name for the present provisionally, but have 
strong doubts as to its claims to rank asa distiact species. The shells 
are always thin, with two sets of radiating strie, the stronger ones. 
distant from one-fourth of a line to one line, and with from three to 
twelve very. fine ones between. | 
Locality and formation.—Oriskany Sandstone, and Corniferous 
limestone. County of Haldimand. 
Collectors.—J. De Cew; E. De Cew. 
SrROPHOMENA DEMIssA.—(Conrad.) 
STROPHOMENA DEMIssA.—UConrad. Journal of the Academy of 
Natural Sciences of Philadelphia. Vol. 8, p. 258, pl. 14, fig. 
14, 1889. SrropHomeEeNna or STROoPHODONTA DEMISsA.—Hall, 
in various works. Compare also S. suspemrssa.—Hall. Tenth 
Ann. Rep. Regents, N. Y. Univ. p. 145, and 8. arcuara.—Hall. 
Geology of Iowa, Vol. 1. Part 2, p. 492, Plate 3, fig. 1, a, 6, ¢, d, 
2. a, 6, ¢. 
Fig, 116. Fig. 117. 
Fig. 116.—One of the forms of 8, demissa, ventral view. 
Fig. 117.—The same specime, dorsal view. 
Fig. 118.—Two views of a very smia!] specimen, 
Description.—Semioval, subquadrate or subtriangular; hinge line 
equal to, greater or less than the width of the shell; cardinal angles 
often forming extended or short acute ears; in some specimens the 
sides and front margin are uniformly curved, giving the semioval form 
represented above, (fig. 116); in others the sides are somewhat 
straight and parallel for two-thirds of the length, and the front margin 
broadly rounded, approaching the subquadrate aspect; others are 
rounded subtriangular, the hinge line being extended and the front 
narrowed, while some have the greatest width in the front half. The 
width varies from a little less to one-third greater than the length. 
