﻿1042 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 



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 rior showing the apical plate, X 10, paratype, u68iog; (73) exterior of the bra- 

 chial valve showing elevated beak and concentric lines, X 10, paratype, 116819b. 

 Horizon and locality same as preceding. 



Plate 19 

 schizocrania, schizotreta, trematis 



A. Schizotreta willardi Cooper, new species 281 



(I) Exterior view of exfoliated brachial valves, X 2, paratype, I09697g; (2) mod- 

 erately well preserved brachial valve showing exterior, X 2, holotype, 109697b; 

 (3, 4) brachial exterior, X 2, respectively a replica of the exterior made from 

 an impression and the counterpart of the impression, paratypes, 109697c, f; 

 (5) exfoliated pedicle valve, X 2, paratype, 109697c; (6) somewhat exfoliated 

 pedicle valve showing foramen track, X 2, paratype, 109660a. 



Pratt Ferry formation, 0.2 mile south of Pratt Ferry, Blocton (15') Quad- 

 rangle, Ala. 



B. Schizotreta shuleri (Willard) 280 



(7) Brachial valve showing ornamentation well, X 2, hypotype, 109699c; (8, 9) 

 side and apical views of a partially exfoliated pedicle valve, X 2, hypotype, 

 109699a. 



Rich Valley formation, Porterfield Quarry, 5 miles east of Saltville, Maccrady 

 (T.V.A. 218-NW) Quadrangle, Va. 



C. Trematis sp. 3 275 



(II) Imperfect brachial valve, X 3, figured specimen, 109704, (10) enlargement 

 of same, X 6, showing external pits. 



Lower Edinburg (Cyrtonotella zone), & mile east of Strasburg Junction, 

 Strasburg (15') Quadrangle, Va. 



D. Trematis foerstei Cooper, new species 271 



(18, 15) Pedicle valve, X 1 and X 2, holotype, I09707d; (16) plasticine replica of 



the exterior of a pedicle valve, X I, paratype, 109709a; (17) the brachial valve, 

 X 1, paratype, I09709d; (19) ornamentation, enlarged X 4, of preceding. 



Plattin (Macy) or Barnhart formation (upper 10 feet), Yaeger Farm, 3 miles 

 northwest of Frankford, si miles southeast of New London, Ralls County, Mo. 



E. Trematis parva Cooper, new species 273 



(13) Exfoliated brachial valve, X 3, paratype, 109705a. 



Lower Whitesburg formation, \ mile west of Bulls Gap, Bulls Gap (T.V.A. 

 171 -SE) Quadrangle, Tenn. 

 (14, 12) Brachial valve preserving exterior, X 3 and X 6, holotype, 109703. 



Chatham Hill formation, Grayson Farm, 4 miles southwest of Bland, Va. 



F. Schizomania filosa (Hall) 275 



(20) Cluster of small individuals on a Rafinesquina shell, X 3, figured specimen, 

 109711 ; (21) brachial valve, X 2, of a large individual on the same slab. 



Plattin group (Macy formation) or Barnhart formation (upper 10 feet), 

 mouth of Big Creek, Ralls County, Mo. 



G. Schizotreta sp. 1 282 



(22) Exterior of partially exfoliated pedicle valve, X 4, figured specimen, 109650. 

 Lincolnshire formation (Hogskin member — upper 30 feet), road to Washburn, 

 4i miles west-southwest of Thorn Hill, Avondale (T.V.A. 162-SW) Quad- 

 rangle, Tenn. 



Plate 20 



Orbiculoidea, Schizotreta 



A. Schizotreta microthyris Cooper, new species 278 



(1) Exfoliated brachial valve, X 2, paratype, 97547a; (2) partially exfoliated 



