SILURIAN FAUNAS. 22% 
189%. Stropheodonta nearpassi Schuchert, Bull. U. S. Geol. Surv., 
VaNow sis, ps 425. 
1897. Stropheodonta textis Schuchert, Bull. U. S. Geol. Surv., No. 
87, p. 427. 
1897. Strophomena (?) bipartita Schuchert, Bull. U. 8. Geol. Surv., 
No. 87, p. 429. 
Description.—Shell with thin, nearly-flat brachial valve and slghtly- 
convex pedicle valve, longitudinally subsemi-elliptical in outline, the 
hinge-line produced beyond the body of the shell into mucronate ex- 
tensions, hinge-line crenulate. Surface of both valves marked by fine, 
irregularly alternating, angular, raised striz, which are not continuous 
over the umbo to the beak, and which curve outward on the sides of 
the shell in passing to the margin, the curvature becoming stronger 
on approaching the hinge-line. The surface is also marked by much 
finer, crowded, concentric lines, which continue to the beak. Oblique 
wrinkles along the cardinal margin are present in many specimens. 
The interior of the valves, more especially the pedicle, is covered with 
fine, closely-crowded papille, which gives to the surface of internal 
casts a finely-pitted or punctate appearance. These internal papille 
may frequently be detected through the thin shell substance as dark 
spots, giving it a punctate appearance, but there are apparently no 
perforations. ‘The muscular impressions of the pedicle valve are 
rather large and divergent and are free from impressions of papille. 
In the interior of the brachial valve a low median ridge reaches more 
than half way to the front of the shell. 
The dimensions of a medium-sized specimen are: length, 28 mm., 
and breadth, 30 mm. 
Remarks.—This species is a variable form, and undoubtedly in- 
eludes the three shells described by Hall under the names Leptena 
sp., Leptena bipartita and Strophodonta textilis, all from 
the Coralline limestone at Schoharie, New York. The name Stropho- 
donta nearpasst was applied by Barrett to specimens from New Jersey 
from the locality where most of our material was:secured. If the 
generic or subgeneric name Leptostrophia, given by Hall and Clarke 
to the very flat forms of Stropheodontas, is to be retained, the present 
species will be there included. 
