PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 985 
porella in the form of its cardinal process and notothyrial chamber. It is frequent 
in punctate shells for the median septum to be continued posteriorly along the 
floor of the notothyrial chamber and unite with the shaft of the cardinal process. 
Such is the case in Elasmothyris, and the brachial structures are in support of 
the idea that the shell is punctate. Specimens of Elasmothyris are very small 
and not always well preserved, but the cardinal process appears to have a bulbous 
or expanded myophore such as that of Linoporella or other dalmanelloid brachio- 
pods. The latter feature and the posterior continuation of the median septum 
differentiate Elasmothyris from the other skenidioid genera mentioned above. 
ELASMOTHYRIS CONCINNULA Cooper, new species 
Plate go, F, figures 35-42 
Shell minute, wider than long and with the hinge less than the midwidth; 
sides gently rounded; anterior margin broadly rounded to truncated; anterior 
commissure strongly sulcate. Surface costellate, costellae increasing by inter- 
calation ; anteriorly somewhat fascicostellate. 
Pedicle valve moderately convex in lateral profile, with the maximum con- 
vexity in the posterior third; anterior profile domed and narrowed medianly. 
Umbonal and median region swollen to form a low fold extending from beak to 
anterior margin. Flanks on each side of fold descending steeply to the margins. 
Interarea long; beak slightly incurved. Interior as described for the genus. 
Brachial valve unevenly convex with the posterior somewhat flattened and the 
anterior curved moderately toward the pedicle valve ; umbo gently convex; sul- 
cus originating just anterior to the umbo, widening and deepening anteriorly to 
the margin where a short tongue is formed. Flanks bounding sulcus moderately 
swollen; posterolateral extremities deflected toward the pedicle valve and flat- 
tened. Interior as described for the genus. 
Measurements in mm.—Holotype, length 1.2, brachial length 1.3, midwidth 
1.5, hinge width 1.3, thickness 1.0. 
Types.—Holotype: 117371a; figured paratypes: 117371b-d. 
Horizon and locality—Pratt Ferry formation in Alabama: 0.2 mile southeast 
of Pratt Ferry, Blocton (15’) Quadrangle. 
Discussion.—No other species of this genus is known to which this one may 
be compared. 
Family SCHIZOPHORIIDAE Schuchert, 1929 
Dalmanellacea having lenticular or resupinate profile and fine costellae ; brach- 
ial interior characterized by erect, subparallel to divergent brachiophore support- 
ing plates and slender, solid brachiophores; sockets defined by fulcral plates. 
Subfamily ScH1zopHoRIINAE Schuchert, 1929 
Finely costellate, unplicated Schizophoriidae. 
