636 TRANS. OF THE ACAD. OF SCIENCE. 
into the small arched ears. Surface marked by small, round- 
ed, granulated, irregular, radiating plications, whose number 
is increased by subdivisions and implantations. 
Length, 1.45; breadth, 1.11; depth of ventral valve, .94. 
At the base of the Devonian rocks, in Callaway county, 
associated with Wautilus Lawsii, Strophodonta cequicostata, 
S. infleca and 8. altidorsata, etc., ete. 
STROPHODONTA SUBCYMBIFORMIS, nh. sp. 
Shell very convex, suborbicular, or subquadrate. Ventral 
valve very convex, highest near the umbo; slightly curved 
towards the anterior margin, and more abruptly towards the 
beak ; rounded or subcarinated along the middle, flattened 
towards the lateral margins; ears large, distinct, semi-cylin- 
drical or arched, projecting a little beyond the lateral mar- 
gins; umbo large, depressed, projecting somewhat beyon 
the cardinal line; beak small, depressed, projecting a little 
over the area; area straight, narrow and depressed. Dorsa 
valve less convex, leaving much room between it and the op- 
posite valve, flattened towards the area; lateral margins re- 
curved to form the arched ears; a deep, broad, rounded de- 
pression in front to meet the convexity of the opposite valve. 
Surface marked with small, high, rounded, irregular, granula- 
ted, radiating plications; increased by subdivisions and im- 
plantations. 
Length, 1.38; breadth, 1.45; depth of ventral valve, 84. 
This species is most like S. cymbiformis, but is more “4 
gularly convex, broader, not so abruptly arched transverse y 
along the center of the ventral valve, and the cardinal line 18 
nearer the extremity. 
At the base of the Devonian rocks in Callaway county, 
associated with the same species as the last. 
SrrRoPHODONTA KEMPERI, 0. Sp. 
Shell symmetrically semiovoidal, regularly costate. Ven- 
tral valve very regularly convex, slightly de 
the ears; umbo large, rounded, prominent; 
cave, orbicular, slightly depressed in front; carding Be 
shorter than the width of the shell. Surface ornamente Mia 
humerous small unequal, granular, i 
distinct lines of growth; coste increased by 1mpian’s less 
is species differs from the cymbiformis, 1n being oo 
convex and ovate, in having regular coste, and in being 
