70 
Aug. F. Foerste 
Brownsport bed : east of William Goodwin on Coon creek, two ) 
and two-tenths miles east of Linden, near base of exposures on i 
hill side, Tennessee. 
Gypidula simplex, sp. nov. 
{Plate III, Figs. 51 A, B.) 
Shell small, smooth, plicated near the anterior edge. On the |! 
pedicel valve two low plications, 3 mm. apart in a shell having a { 
width of about 21 mm., rise sufficiently to form a low median fold | 
along the anterior third of the valve. On the anterior third of the j 
brachial valve there is a corresponding broad shallow sinus, with j| 
a low median plication. There may be an additional smaller pli- ( 
cation along the median line of the pedicel valve, and the median 
plication of the brachial valve may be divided by a narrow 
furrow into two plications. This shell probably is closely related 
to Gypidula angulata, Weller. 
Waldron bed: Newsom, Tennessee. 
Gypidula roemeri, Hall and Clarke. 
{Plate III, Fig. 51 C.) I 
The shell figured here is intermediate between Gypidula simplex 
and typical Gypidula roemeri. 
Waldron bend: Newsom, Tennessee. 
Platymerella manniensis, sp. nov. 
{Plate I, Figs. l A, B, C, D.) j 
Elongate, equally biconvex pentameroid; not galeatiform, pedi- 
cel valve not overarching, and without distinct fold or sinus; 
without distinct cardinal area. The beaks of the pedicel and 
brachial valves are practically in contact with one another, so that 
the delthyrium can not be seen; the beak of the pedicel valve rises 
slightly higher than that of the brachial valve. The dental plates 
of the pedicel valve are united so as to form a spondylium sup- ! 
ported by a median septum; this septum appears to be supported 
along its entire length by the interior of the shell, but it is very 
short, about 6 mm.; the spondylium is small and appears to be 
confined to the immediate vicinity of the beak. Cross-sections of 
the shell at the beak show crural plates, moderately convergent. 
