694 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
pied by a narrowly rounded fold bearing a slight median longitudinal groove. 
Furrows defining median fold deep; folds bounding sulcus low but narrowly 
rounded. Median septum extending to point of origin of median fold. 
Measurements in mm.—Holotype, length 4.0, width 3.6, thickness 2.3. 
Type—Holotype: 111390. 
Horizon and locality—Rysedorf conglomerate, near Albany, N. Y. 
Discussion.—This species is close in form and outline to C. sulcata, but unlike 
that species it is costate on the flanks, a feature uncommon in later species of 
Cyclospira as far as known. The Rysedorf species differs from the Tennessee 
one in having an elongated and narrow beak and a strong, narrow median fold 
in the sulcus of the brachial valve. This species is placed in Cyclospira because 
of the long, prominent, and thick median septum. The exterior resemblance to 
Protozyga is striking, but the median septum is stronger than usual in that genus. 
CYCLOSPIRA PARVA Cooper, new species 
Plate 142, K, figures 49-53 
Shell small for the genus, subpentagonal in outline, with the greatest width lo- 
cated at about the middle; lateral margins rounded; front margin narrowly 
rounded ; surface smooth. 
Pedicle valve with strongly incurved beak; umbo and beak in profile forming 
an acute angle. Umbo swollen and somewhat carinated, extended forward to the 
front margin as a narrowly rounded fold. Fold flattened in the anterior third; 
flanks in anterior profile forming an angle of about 90°, flattened to slightly con- 
cave and with steep slopes to the margins. 
Brachial valve about a third as deep as the pedicle valve, gently convex in lat- 
eral profile; umbonal region slightly inflated; sulcus originating just anterior to 
the umbo and extending to the front margin, widening and deepening anteriorly. 
Flanks bounding sulcus well rounded and with moderately steep lateral slopes. 
Interior: Median septum extending about half the length of the valve; spire 
extending well beyond the middle. 
Measurements in mm.—Holotype, length 4.1, width 3.6, thickness 2.3. 
Types.—Holotype: 111391a; unfigured paratypes: 111391b-d. 
Horizon and locality—Bromide formation (Pooleville member—O-oplecia 
gouldi zone) in Oklahoma: Rock Crossing of Hickory Creek, about center sec. 
35, 1.5 9., R. 1 E., Criner Hills, Carter County. 
Discussion.—This species is smaller than C. sulcata, which it resembles, and 
has a shorter sulcus. C. sulcata gives a more square-shouldered appearance than 
the Oklahoma species. 
CYCLOSPIRA PRECIOSA Cooper, new species 
Plate 141, E, figures 25-32 
Shell moderately large for the genus, length and width of a large adult about 
equal; pentagonal in outline; sides rounded and with the maximum width at or 
