320 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Costellae crossed by fine elevated fila, about 5 in 1 mm. near the center of the 
pedicle valve. 
Pedicle valve moderately convex in lateral profile with greatest convexity lo- 
cated in the posterior half; anterior profile with a low hump medially from 
which the sides descend in a slightly concave slope. Median region from umbo 
to anterior margin moderately swollen to form a poorly defined fold. Umbo con- 
vex, beak protruding slightly posterior to the posterior margin. Flanks flat or 
slightly concave and descending gently to the margins. Umbonal slopes moder- 
ately steep. Interarea slightly longer than the one on the brachial valve, strongly 
curved, anacline to apsacline. 
Brachial valve flat to gently concave in lateral profile, sulcus originating at 
the beak, shallow, and generally disappearing in the anterior half to third which 
is flattened to meet the anterior margin. Flanks flat to very gently convex; 
cardinal extremities flattened. Interarea long, flat, anacline. 
Brachial interior with erect cardinal process having a short shaft, trilobed myo- 
phore in which the median lobe is carinate and elevated, suggesting that of Val- 
courea. Median ridge short, not reaching one-third the length. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
Hypotype (110349a)........ 2Iat 20.3 26.8 24.7 5.1 
ss Ci10948a 0.) 16.6 16.0 19.8 20.6 5.0 
e €110348b) tion 13.4 12.9 16.0 14.7 ? 
Types—Holotype: Y.P.M. S764; figured hypotypes: 110348a,b; measured 
hypotype: 110349a. 
Horizon and locality——Lincolnshire formation (Hogskin member) in Ten- 
nessee: On the Sally Cleveland Farm, $ mile southwest of Washburn, Dutch 
Valley (T.V.A. 154-SE) Quadrangle ; on the road to Washburn, 43 miles west- 
southwest of Thorn Hill, Avondale (T.V.A. 162-SW) Quadrangle; Maynard- 
ville Pike, 1.7 miles north of Hall Crossroads, Fountain City (T.V.A. 146-SW) 
Quadrangle. 
CYRTONOTELLA CRASSICOSTELLA (Schuchert and Cooper) 
Planidorsa crassicostella ScHUCHERT and Cooper, Mem. Peabody Mus. Nat. Hist., vol. 4, 
pt. 1, p. 101, pl. 16, figs. 22, 27, 1932. 
Type.—Holotype: Y.P.M. 763. 
Horizon and locality—Benbolt formation in Virginia: Speers Ferry, Clinch- 
port (T.V.A. 188-NW) Quadrangle. 
CYRTONOTELLA FASCICULATA Cooper, new species 
Plate 41, A, figures 1-3 
Shell small for the genus, more than 14 times wider along the hinge than long; 
cardinal extremities alate, acutely angular. Lateral margins sloping inward ; an- 
terior margin broadly rounded. Anterior commissure slightly sulcate. Surface 
