PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 491 
Measurements in mm.—117057, length 7.9, brachial length 8.2, width 10.7, 
hinge width 9.3, thickness 4.1. 
Figured specimen.—117057. 
Horizon and locality—Tulip Creek formation in Oklahoma: 152 feet above 
the top of the basal sand, on the first creek east of U. S. Highway 77, 
SESNEILNE4S sec. 25, T. 2S., R. 1 E., Carter County. 
Discussion.—This is clearly an immature form probably not directly compara- 
ble to any of the described species. 
MIMELLA sp. 3 
Plate 91, J, figure 40 
This is a large species which was taken from limestone of the Lincolnshire 
formation along the railroad just east of Strasburg Junction, Strasburg (15’) 
Quadrangle. The brachial valve only is represented, but it indicates a species 
larger than M. laticardinia. It is 22 mm. long by 29 mm. wide. 
Figured specimen.—117058b. 
Family SKENIDIIDAE Kozlowski, 1929 
Small subpyramidal Orthacea probably derived out of Finkelnburgiidae, hav- 
ing a free spondylium, a cruralium, and fulcral plates forming the sockets. 
Genus SKENIDIOIDES Schuchert and Cooper, 1931 
Skenidioides ScHUCHERT and Cooper, Amer. Journ. Sci., vol. 22, p. 243, 1931; Mem. Peabody 
Mus. Nat. Hist., vol. 4, pt. 1, p. 71, 1932. 
SKENIDIOIDES ANTHONENSIS (Sardeson) 
Plate 98, H, figures 31-37 
Skenidium anthonensis SARDESON, Minnesota Acad. Nat. Sci., Bull. 3, p. 333, pl. 4, fig. 7, 1892. 
Scenidium halli Hatt and CLARKE (part), Pal. New York, vol. 8, pt. 1, p. 242, pl. 7A, 
figs. 37-39, 1892. 
Scenidium anthonensis (Sardeson) WINCHELL and ScHUCHERT, Geol. Minnesota, vol. 3, 
p. 381, figs. 20-23, 1893. 
Skenidioides anthonensis (Sardeson) ScHucHERT and Cooper, Mem. Peabody Mus. Nat. 
Hist., vol. 4, pt. 1, p. 71, 1932. 
Shell small for the genus, wider than long, width about twice the length ; cardi- 
nal extremities acute; sides obliquely rounded and sloping toward the middle; 
anterior commissure strongly and narrowly sulcate; surface costate, 10 to II 
costae on each side of the fold and sulcus; fold marked by 3 or more costae, the 
outer 2 bifurcated, the inner ones may or may not be bifurcated depending on 
the size attained; sulcus with a similar arrangement. 
Pedicle valve gently convex in lateral profile; broadly triangular in anterior 
profile; anterior commissure deeply emarginate at the fold; flanks bounding 
fold gently convex in anterior profile ; fold only slightly elevated. Interarea long, 
beak gently curved. 
