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PALAEONTOLOGY OF NEW-YORK. 
Strofiliodonta inequistriata. 
PLATE XVIII. 
Strophomena inequistriata : Conrad, Jour. Acad. Nat. Sciences, Philadelphia, 1842, Volviii, pa. 254, 
pi. 14, f. 2. 
Strophomena inequistriata : Hall, G’eol. Rep. 4th District, 1843, p. 290, f. 4. 
Compare Orthis interstrialis : Phillips, Pal. Fossils, 1839, pa. 61, pi. 25, f. 103 o, 6, c. d. 
Strophomena ( Strophodonta ) inequistriata : Hall, in Tenth Report on the State Cabinet, p. 142. 1857. 
Shell semioval or somewhat semicircular in outline : hinge-line extended 
beyond the width of the shell below; extremities acute, sometimes 
auriculate. Rarely the sides are nearly straight below the auricu- 
late extremities, and the basal curve rather straightened on each side 
and produced in a subnasute extension in the middle. 
Ventral valve usually regularly convex, and often more gibbous in the 
middle and abruptly arched towards the hinge-line, depressed-convex 
on the disc, with the margin towards the front more abruptly curving; 
sometimes gently sloping towards the front and abruptly constricted 
on the sides below the cardinal extremities, which are deflected to the 
ventral side : the beak is small, scarcely prominent on the hinge-line. 
Dorsal valve moderately concave, often more deeply concave; some¬ 
times moderately concave in the upper and middle part, and suddenly 
deflected towards the front. 
Area of the ventral valve narrow-linear, extending to the extremities 
of the hinge-line, striate vertically, with the inner margins crenulate 
from one-half to two-thirds the length from the beak to the extremi¬ 
ties : foramen none; a slight linear elevation extends across the 
area. Dorsal area scarcely more than half as wide as the ventral area, 
and, in very perfect specimens, having a narrow elevated ridge cross¬ 
ing it in continuation of that of the opposite 'valve. 
Surface of the entire shell marked by slender distant elevated striae, 
which are increased by interstitial additions; the interspaces occupied 
by much finer closely arranged striae, which are scarcely visible to the 
naked eye, and crossed by fine concentric striae. 
