NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA — GRANT JJ 



spondylium is sessile for less of its length. The rather low convexity, 

 costate umbones, bifurcating costae, low fold, and lack of fine concen- 

 tric ornamentation distinguish this species from species of Coledium 

 with which it occurs in the Chappel Limestone. 



Occurrence and abundance. — Chappel Limestone, 0.55 mile N. 39 

 W. of High Lonesome Windmill, 8 miles SE. of Brady, Bald Ridge 

 area, McCulloch County, Tex. (locality TF-406 of Cloud and Barnes, 

 1948) (98 specimens USNM 142041); Chappel Limestone, 3,800 

 feet NE. of Elm Pool, Johnsons City area, Blanco County, Tex. (lo- 

 cality 16T-2-27A of Cloud and Barnes, 1948) (5 specimens USNM 

 142042) ; Chappel Limestone, 600 feet SW. of mouth of Joe Davis 

 Hollow, San Saba River, southeast McCulloch County, Tex. (9 speci- 

 mens USNM 142043). 



Age. — Early Mississippian (Kinderhook). 



Subfamily PSILOCAMARINAE Grant n. subfam. 



Atriboniidae with intercamarophorial plate absent or rudimentary, 

 hinge plate divided or short. 



Genus PSILOCAMARA Cooper 1956 



Levicamera GRABAU, A. W., 1934, Paleont. Sinica, ser. B, vol. 8, fasc. 3, p. 18. 

 Psilocamara COOPER, G. A., 1956a, Journ. Paleontology, vol. 30, No. 3, p. 523. 

 NOT Laevicamera GRABAU, A. W., 1936, Paleont. Sinica, ser. B, vol. 8, fasc. 4, 



p. 87 (= Camerisma n. gen.). 

 NOT Levicamera Grabau, SARYCHEVA, T. G. and SOKOLSKAYA, A. N., 



1952, Trudy Paleont. Inst. Moscow, vol. 38, p. 171 (= Camerisma n. gen.). 



Shell small for family, strongly biconvex, subglobose to subpyram- 

 idal ; outline subtrigonal to subpentagonal ; anterior commissure 

 strongly uniplicate ; fold high, ogival, crest blunt to sharp, some sloping 

 without break toward flanks, normally smooth; sulcus shallow, with 

 weak median groove corresponding to crest of fold, anterior extended 

 as tongue, curved around margin ; flanks smooth, without costation ; 

 valve edges butting around most of commissure, brachial valve slightly 

 overlapping posterolateral edge of pedicle valve ; valve edges nowhere 

 flexed or extended to form stolidium ; growth lines fine, closely spaced ; 

 fine radial ornament absent. 



Pedicle valve moderately strongly convex transversely, strongly 

 convex longitudinally ; umbonal region somewhat swollen, flanks rela- 

 tively flat; beak short, blunt, straight to suberect; beak ridges gently 

 rounded, barely discernible ; delthyrium small, triangular, constricted 

 at sides by small, triangular, disjunct deltidial plates, leaving elongate, 

 slitlike foramen, partly filled by beak of brachial valve; posterolateral 



