274 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
pedicle valve when found will indicate a new genus. The definite median sulcus 
is another feature quite unlike that of Tremaits ss. 
TREMATIS ? SPINOSA Cooper, new species 
Plate 11, I, figures 22-24 
Known from the brachial valve only ; thin shelled, light to dark brown in color, 
subcircular in outline ; lateral and anterior margins strongly rounded ; gently con- 
vex in lateral profile and with the greatest convexity in the umbonal region; 
anterior profile broadly convex with moderately steep slopes and swollen median 
region. Surface marked by densely crowded pits; margin marked by fine hair- 
like spines ; spiny margins preserved in late growth varices. Interior with a small 
concave plate overhanging the umbonal cavity. 
Type.—Holotype: 116810. 
Horizon and locality—Pratt Ferry formation: 0.2 mile southeast of Pratt 
Ferry, Blocton (15’) Quadrangle. 
Discussion.—This peculiar little shell is most closely allied to T. ? parva from 
the Grayson Farm in Virginia, although no spines were seen on the Virginia 
shell. 
TREMATIS sp. 1 
Plate 27, D, figure 9 
This species is represented by two poorly preserved brachial valves that have 
somewhat the shape of T. parva but in which the pits, where visible, are more 
like those of true Trematis arranged in rows between longitudinal costellae. The 
best specimen is small, slightly wider than long, with a marginal beak and nar- 
row, prominent umbo. The convexity is moderate in both profiles. 
Measurements in mm.—117970, length 4.2, width 4.7. 
Figured specimen.—117970. 
Horizon and locality—Whitesburg formation in Tennessee: 4 mile west of 
Bulls Gap ; 24 miles southeast of Whitesburg, Bulls Gap (T.V.A. 171-SE) Quad- 
rangle. 
TREMATIS sp. 2 
A second undescribed species of Trematis is indicated by five specimens, all 
brachial valves, from Whitesburg formation in the railroad cut 1 mile south- 
west of Otes, Bulls Gap (T.V.A. 171-SE) Quadrangle, Tenn., where it occurs 
with Ectenoglossa nymphoidea. This species is strongly convex in both profiles 
and quite oval in outline. The greatest width is located anterior to the middle. 
The beak is strongly incurved and the umbo convex. The median portion is 
swollen and all the slopes to the margins are fairly steep. The costellae are 
very fine. Adjacent pits, in general, are arranged alternately, a pit falling oppo- 
site a crossbar. About 12 costellae appear at the front margin in the space of 
I mm. 
Described specimens.—109702a-e. 
