NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA — GRANT 75 



Table 13. — Measurements of Sedenticellula hamburgensis from the Hamburg 

 Oolite of Weller (1906) of Illinois 



Measurements, in millimeters 



tic molds of three brachial valves illustrated by Weller, 1914, pi. 23, 

 figs. 56-58, Walker Museum No. 13937 (USNM 68188). 

 Age. — Early Mississippian. 



SEDENTICELLULA SACRA Grant n. sp. 



Plate 5, figs. 1-9 



Sedenticellula aff. 5". hamburgensis (Weller) CLOUD, P. E., Jr., and BARNES, 

 V. E., 1948, Univ. Texas Pub. 4621, pi. 44, 12-16. 



Shell large for genus, moderately strongly biconvex; outline sub- 

 elliptical to rounded subpentagonal, elongate or transverse in juveniles, 

 transverse in adults ; anterior commissure with broad, low gentle fold 

 forming arc or flattened arc; fold not standing abruptly higher than 

 flanks of shell; sulcus shallow, slightly depressed below flanks, ex- 

 pressed mainly as tongue at anterior filling fold ; valves butting or 

 meeting with narrow flange on posterolateral slopes, meeting acutely 

 along anterior sides, near right angle at anterior; costae fine, low, 

 rounded, beginning at or within 3 mm. of beaks, number increasing 

 toward anterior by intercalation and bifurcation, totaling as many as 45 

 around margins of valve, producing only slight crenulation of commis- 

 sure; concentric growth lines or other fine ornamentation absent; 

 growth laminae weak, widely spaced, rarely observed ; fibrous shell 

 structure producing appearance of fine radial ornamentation. 



Pedicle valve flatly convex, somewhat swollen in umbonal region, 

 flat toward flanks, gently convex through sulcus; beak short, sharp, 



