PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 927 
to make the group useful, but the study will require enormous collections which 
are not now available. 
STROPHOMENA ANOMALA Cooper, new species 
Plate 264, A, figures 1-15 
Shell small for the genus, wider than long; subrectangular in outline; hinge 
equal to or less than the midwidth; sides gently rounded; anterior margin 
broadly rounded. Surface costellate, costellae of unequal size, intercalated in 
several generations and numbering 3 to the millimeter at the front margin. 
Pedicle valve unevenly convex in lateral profile, the posterior half gently con- 
vex but the anterior half gently concave. Umbonal region narrowly swollen and 
forming a prominent narrow fold to about the valve middle or shortly beyond; 
flanks bounding fold forming long, flat to slightly concave slopes to the lateral 
margins; anterior third gently concave to flat; interarea long; pseudodeltidium 
prominent and swollen. 
Brachial valve very gently convex in lateral and anterior profiles; umbo and 
median region marked by a shallow and narrow sulcus which disappears in the 
slight swelling to form the flattened anterior third ; flanks bounding sulcus slightly 
swollen ; posterolateral slopes gentle ; cardinal extremities flattened and deflected 
slightly in the direction of the brachial valve. 
Pedicle interior with muscle area nearly equal in length and width, but the 
anterior ends of the diductor scars elongated; dental ridges thick but not ex- 
tended anteriorly around the adjustor-diductor scars. Brachial valve with small 
cardinal process but median ridge moderately long and stout. 
Measurements in mm.— 
Brachial Hinge 
Length length Midwidth width Thickness 
Holotype. i. «cede seas 12.4 11.2 17.6 17.6 2.8 
Paratype (11770I1d).. 11.3 10.5 15.1 13.7 2.0 
Types.—Holotype: 117700; figured paratypes: 117701a,c,d; unfigured para- 
types: 117700b, 117701b. 
Horizon and locality—Benbolt formation (base) in Virginia: 0.2 mile south 
of the middle fork of Moccasin Creek, 14 miles south of Hansonville, Hanson- 
ville (T.V.A. 205-SW) Quadrangle. 
Discussion —This is a rare species known only from the Benbolt formation. 
It is characterized by fairly strong costellae, a strong median fold in the posterior 
half of the pedicle valve, and nearly even depth of both valves. The species sug- 
gests Pionomena but is actually resupinate although not strongly so. This latter 
feature will distinguish it from the other members of the genus described herein. 
Strophomena ? emaciata Winchell and Schuchert from Minnesota is still more 
biconvex and differently ornamented, so that little confusion will result between 
these two, 
