NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA — GRANT 85 



size, subglobose shape, short beak, smooth exterior, and high fold at 

 the anterior. Rhynchonella hanieli Broili (1916) also may belong to 

 Camarophorina, although its internal characters are not sufficiently 

 known to place it certainly in that genus. It differs from C. antisella in 

 its somewhat larger size, broader outline, flatter profile, and lower, 

 broader fold and sulcus, and slightly stronger growth laminae. Broili 

 (1916, p. 63) considered the two species to be generically distinct, 

 their similar sulcation illustrating convergent evolution. 



Camarophorina antisella differs from C. (?) wettonensis (David- 

 son) from the Carboniferous of Britain in its smaller and more globose 

 form, less flattened crest of the fold on the pedicle valve, and in its 

 total lack of costae. C. (?) zvettonensis has numerous weak costae on 

 the fold, in the sulcus, and on the flanks of both valves. 



Genus CAMAROPHORINELLA Licharev 1936 



Shell subtrigonal, subpentagonal or subelliptical, biconvex ; com- 

 missure uniplicate ; fold low, broad at anterior, standing only slightly 

 above flanks ; sulcus shallow, producing only short tongue at anterior ; 

 costae low, rounded, numerous, beginning at or near beaks, number 

 increasing anteriorly by bifurcation or intercalation ; valves meeting 

 acutely at anterior ; stolidium absent ; growth laminae distinct, widely 

 spaced. 



Pedicle valve moderately convex ; beak short, sharp ; curvature of 

 beak, form of delthyrium and foramen, and possibility of presence of 

 deltidial plates not observed. 



Brachial valve more strongly convex ; beak short, probably curved 

 into delthyrium of pedicle valve. 



Pedicle valve interior with large dental plates converging toward 

 floor, meeting just above floor to form large, boat- shaped spondylium ; 

 median septum formed by juncture of dental plates on midline, low and 

 thick at posterior, becoming slightly higher and much thinner ante- 

 riorly ; height of dental plates decreasing anteriorly, hence spondylium 

 reduced to shallow concave platform at anterior end. Muscle marks not 

 observed. 



Brachial valve interior with small, irregularly fimbriate cardinal 

 process at apex. Hinge plate divided anterior to process ; camarophor- 

 ium on median septum, posterior edges attached to underside of hinge 

 plate ; intercamarophorial plate absent ; camarophorium extending 

 anteriorly beyond hinge plate, curving ventrally, height of septum in- 

 creasing anteriorly ; crura extending anteriorly from forward edges of 

 hinge plate, continuing near edges of camarophorium. Muscle marks 

 not observed. 



