PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 263 
UNDIFERINA RUGOSA Cooper 
Plate 18, B, figures 8-21 
Shell small, subrectangular in outline with a straight hinge but irregular sides 
and anterior margin ; sides generally somewhat narrowly rounded ; anterior mar- 
gin usually broadly rounded, often irregular, sinuate or emarginate on one side. 
Surface marked by fine concentric lines superimposed over irregular shell undula- 
tions and knobs. 
Interior as described for the genus. 
Measurements in mm.— 
Length Width Thickness 
PEC CRRDERE | ea tier n & voccaas ay grt besa e) ous: viicuahoue ar oamicuaee 1.8 Bur 0.5 
BORE NUT AERS TOA) is ci 6 eras. re se as erue. eee 2.0 2.6 0.5 
ve UTMOSSZE) cwuieoece oleie ve ote Ore oes 1.9 2.6 0.6 
Types.—Holotype: 116832b; figured paratypes: 116832a,c-f; unfigured para- 
types : 116832¢,h. 
Horizon and locality—Pratt Ferry formation (lower 3 feet) in Alabama: 0.2 
miles southeast of Pratt Ferry, Blocton (15’) Quadrangle. 
Discussion.—No other species is known to which this one may be compared. 
Superfamily StIpHONOTRETACEA Schuchert and Walcott, 1908 
Family SIPHONOTRETIDAE Kutorga, 1848 
Usually oval shells with an oval or subcircular pedicle opening at the apex or 
passing by resorption through the protegulum and umbo. 
Genus SIPHONOTRETA Verneuil, 1845 
Siphonotreta VERNEUIL, Geol. Russia, vol. 2, p. 286, 1845. 
SIPHONOTRETA AMERICANA Cooper, new species 
Plate 14, A, figures I-11 
Shell small for the genus, oval in outline, ornamentation with posterior third 
marked by fine, distant concentric lines and fine radial lines which develop a 
spine at their intersection ; anterior two-thirds finely lamellose, each lamella bear- 
ing one or more rows of fine spines, measuring slightly over 14 mm. at the front 
margin. 
Pedicle valve width equal to about two-thirds the length. Greatest width just 
anterior to the middle; apical angle about 100°. Lateral margins broadly 
rounded ; anterior margin somewhat narrowly rounded. Lateral profile moder- 
ately strongly convex with the maximum convexity located in the umbonal re- 
gion; anterior profile broadly but fairly strongly convex; posterolateral slopes 
rounded and steep. Foramen, small, oval, about 1 mm. long and located just 
anterior to the apex. 
Brachial valve slightly longer than wide with strongly rounded margins and 
gently convex profiles. Umbonal region sulcate, sulcus gradually widening an- 
