688 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Measurements in mm.— 
Length Width Thickness 
Paratype: CIl72500 id vas sie eelicint oom om anes 3.4 2.8 1.8 
a (a Riawba) Foye. Hieyccal vated. Belge Oe 3.6 3.0 1.7 
Types—Holotype: 111416b; figured paratypes: I11414a,c, 111416a; un- 
figured paratypes: 111414b, 117250a. 
Horizon and locality —Benbolt formation in Virginia: At Rye Cove, Clinch- 
port (T.V.A. 188-NW) Quadrangle; 0.2 mile south of the middle fork of Moc- 
casin Creek, 14 miles due south of Hansonville, Hansonville (T.V.A. 205-SW) 
Quadrangle; north side of U. S. Highway 19, about 1 mile due north of Belfast 
Mills, Saltville (T.V.A. 212-NE) Quadrangle. 
Benbolt formation in Powell Station (T.V.A. 137-SE) Quadrangle, Tennes- 
see: 1.6 miles northeast of Heiskell ; road corner $ mile southeast of Fleanor Mill. 
Murfreesboro formation (top) in Tennessee: On the west fork of Stone River 
at its junction with U. S. Highway 70S, 14 miles northwest of Murfreesboro, 
Murfreesboro (15’) Quadrangle. 
Discussion—Protozyga uniplicata may be recognized by its elongate form, 
short beak, and prominent anterior folding. It differs from P. microscopica in 
its narrower form and less convexity; from P. elongata it differs in its much 
shorter beak. It is much less rotund and convex than P. rotunda. 
PROTOZYGA sp. 1 
Plate 142, J, figures 44-48 
Shell of about usual size for the genus, longer than wide ; oval to subpentagonal 
in outline ; posterolateral margins forming an angle of about 90°. Lateral margin 
broadly rounded ; anterior margin narrowly rounded. Surface marked by short 
costae at the margins, 3 or 4 on each side. 
Pedicle valve moderately convex in lateral profile and with the maximum con- 
vexity at the umbo or just anterior to it; anterior profile narrowly convex and 
with steep sides; umbo and median region forming a subcarinate fold which ex- 
tends to the anterior margin ; fold marked by a shallow sulcus beginning at about 
the middle of the valve and extending to the anterior margin; sulcus in fold 
marked by a single costa extending the length of the sulcus; flanks nearly flat 
and very steep. 
Brachial valve gently convex in lateral profile and with the maximum con- 
vexity just anterior to the umbo; anterior profile broadly convex but marked by 
a narrow and shallow depression at the middle; umbonal and median region nar- 
rowly sulcate; sulcus widening abruptly at the middle and extending to the an- 
terior margin where it occupies more than half the width; sulcus occupied by 2 
strong costae separated by a narrow sulcus which corresponds to the median 
costa of the opposite valve. Flanks moderately convex and with steep postero- 
lateral slopes. 
Measurements in mm.—111392<, length 4.0, brachial length 3.7, midwidth 3.2, 
widest part 3.3, thickness 2.0. 
