PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 603 
plates in the pedicle valve and a cruralium in the brachial valve. Exteriorly this 
genus is smooth but has rotund moderately uniplicate shells. Stenocamara differs 
from Xenelasma in having exceptionally long dental plates and an exceedingly 
narrow delthyrial chamber, whereas these features in the Canadian genus are 
shorter and wide. In the brachial valve the two also differ. Xenelasma is 
characterized by an elongate and almost sessile cruralium; the same structure 
in Stenocamara is short and like that of Camerella. This genus thus combines 
features of the camerellids and of the syntrophids. 
STENOCAMARA BICOSTATA Cooper, new species 
Plate 115, G, figures 43-48 
Shell small, slightly wider than long; greatest width slightly anterior to the 
middle ; beak slightly greater than a right angle, posterolateral margins straight ; 
lateral margins narrowly rounded; front truncated. Surface smooth in the pos- 
terior half and on the flanks. Sulcus with 2 costae and the fold with 3. 
Pedicle valve slightly convex with the greatest convexity at the umbo; sulcus 
originating at about the middle, wide and shallow, occupying more than half the 
shell width; tongue short. Midregion slightly swollen. Flanks slightly concave 
and with very gentle slopes to the margins. Interior with long, slightly diverging 
dental plates. 
Brachial valve gently convex in the anterior part but strongly convex in the 
umbonal region; strongly convex in anterior profile; swollen in the midregion. 
Fold originating anterior to the middle, low, and bearing in its median region a 
longitudinal depression occupied by a costa depressed below those bounding the 
fold. Costae forming margins of fold angular and strong; flanks narrowly 
rounded and with steep slopes. 
Measurements in mm.—Holotype, length 5.8, brachial length 5.4, width 6.2, 
hinge width 1.9, thickness 4.1. 
Type.—Holotype: 111317. 
Horizon and locality—Mosheim formation in Alabama: 4 mile east of Oden- 
ville, Springville (30’) Quadrangle. 
Discussion.—This species differs from S. perplexa in its small size and the 
presence of strong costae at the anterior. 
STENOCAMARA PERPLEXA Cooper, new species 
Plate 111, E, figures 41-45; plate 119, C, figure 8; plate 268, H, figures 33-40 
Shell of moderate to large size for the genus, length and width about equal; 
widest anterior to the middle. Hinge narrow; outline triangular to ovate; sides 
gently curved ; anterolateral extremities narrowly rounded ; anterior margin trun- 
cated, sides and pedicle beak forming an angle of about 93°. Valves unequally 
convex, the brachial valve having the greater depth. Surface smooth. 
Pedicle valve gently convex in lateral and anterior profiles; umbo and antero- 
umbonal region gently swollen; sulcus broad and shallow, originating at about 
the valve middle; tongue short and squarish. Surface of sulcus convex; sulcus 
