PART. \E CHAZYAN AND RELATED BRACHIOPODS—COOPER 651 
Types.—Holotype: 117228b; figured paratypes: 117228a,c. 
Horizon and locality—Witten formation in Tennessee: 4 mile south of Hei- 
skell, Powell Station (T.V.A. 137-SE) Quadrangle; near Luttrell. 
Discussion.—This species has been confused with FR. ainslei, but it is much 
smaller and has different proportions. It is much more likely to be confused with 
R. rotunda because, like that species, it has smooth rounded outlines and mod- 
erate size. Rostricellula rotunda, however, has a less prominent fold in the adult 
condition, is less deeply sulcate and somewhat deeper. Rostricellula transversa 
is similar but is less numerously costate and is more strongly folded. 
ROSTRICELLULA TRANSVERSA Cooper, new species 
Plate 132, G, figures 38-42; plate 134, E, figures 47-53; plate 137, H, figures 53-60 
Shell of about medium size for the genus with the width equal to about 14 times 
the length ; beak obtusely angular, posterolateral margins straight, sides narrowly 
rounded. Front margin truncated. Surface costate, 3 to 4 costae occupying the 
sulcus and 4 to 5 forming the fold; flanks with as many as 8 costae. 
Pedicle valve moderately convex with the greatest convexity located in the 
posterior half. Umbo swollen and convex; sulcus originating about 4 mm. an- 
terior to the beak, widening anteriorly to occupy about half the width at the 
front. Tongue moderately long, truncated anteriorly. Umbonal slopes steep ; 
flanks flattened in profile and with only moderately steep slopes to the margins. 
Interarea small. 
Brachial valve slightly deeper than the pedicle valve, evenly but moderately 
convex with the maximum convexity at about the middle. Umbonal region flat- 
tened ; umbo marked by a slight depression posterior to the fold which originates 
about 24 mm. anterior to the beak. Fold flattened in anterior profile, moderately 
elevated above the flanks. Steep slopes and a rounded profile characterize the 
flanks. 
Measurements in mm.— 
Brachial 
Length length Width Thickness 
Holotypentitiy. “oot aed ee i..2 8.1 m3 10.6 5.8 
Patatype GAtis45b)) iis. aspects bads.s's 9.1 8.7 11.9 6.2 
+ (GR 210 A ee 10.2 9.3 um ie 7.0 
Types.—Holotype: 111545a; figured paratype: 117229a; figured specimen: 
117230; measured paratype: 111545b. 
Horizon and locality——Bromide formation (Pooleville member) in Oklahoma 
in Murray County: 15 feet below the top of the formation on Colbert Creek, 
SW5 sec. 15, T. 1 S., R. 1 E., 5 miles southwest of Davis ; Spring Creek, N4 sec. 
17, T.2S., R. 1 W., Murray County; in Pontotoc County on Oklahoma High- 
way 99, 3 miles south of Fittstown. Mountain Lake, E4 sec. 22, T.2 S., R.1 W., 
Carter County ; NE# sec. 32, and SE sec. 33, T.2 S., R. 2 E., in Carter County ; 
4 mile west of U. S. Highway 77, sec. 25, T. 2 S., R. 1 E., north of Ardmore, 
Carter County. 
