NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA GRANT 89 



hinge; dental plates large, thin, reaching to floor in apex but con- 

 verging to form sessile spondylium, joining to form low septum duplex 

 just anterior to apex, elevated slightly by septum toward antetrior, 

 spondylium extending anteriorly between one-fifth and one-fourth 

 length of shell, septum continuing slightly farther ; muscle marks and 

 other internal features not observed. 



Brachial valve interior with undivided hinge plate, slightly swollen 

 in apex to form cardinal process ; camarophorium beginning in apex, 

 supported by high median septum duplex, lateral edges of spoon di- 

 rectly butting against underside of hinge plate on one or both sides ; 

 intercamarophorial plate short and weak, or absent ; hinge plate short ; 

 camarophorium curving slightly ventrally and greatly widening, length 

 more than one-third length of shell, nearly half length of valve ; ante- 

 rior edge of septum concave, length of septum on floor slightly greater 

 than length of camarophorium ; crura extending from anterior edge of 

 hinge plate, somewhat shorter than camarophorium ; muscle marks and 

 other internal features unknown. 



Type species. — Cyrolexis haquei n. sp., named for A.F.M.M. Haque, 

 Geological Survey of Pakistan. 



Additional species. — Terebratula super stes Verneuil (1845), long 

 included in Ccmtcrophoria or Stenoscisma, is strikingly similar ex- 

 ternally to C. haquei. Specimens from near Novgorodsk in the 

 U.S.S.R. (just north of Korea) illustrated by Licharev (1913, pi. 1 ; 

 1960, pi. 48) have all the external features of the genus. Verneuil's 

 drawings (1845, pi. 5a-e) are slightly different, and his description 

 mentions the external generic characters of closely curved pedicle beak, 

 weak plication, low and short fold, shallow sulcus, and entirely closed 

 pedicle foramen. The major differences from C. haquei are its larger 

 size, narrower outline, somewhat lower fold, and the lack of costae on 

 the flanks. 



Specimens of C. superstes from the Moscow region illustrated by 

 Sarycheva and Sokolskaya (1952, p. 171, pi. 48, fig. 267) also are 

 similar to C. haquei in profile and outline. However, the valves pro- 

 trude slightly at the fold and sulcus, indicating either an incipient sto- 

 lidium, or perhaps a stolidium that was broken from the specimens. 

 Possibly these specimens also belong to Cyrolexis; direct study of the 

 specimens is necessary. 



According to Tschernyschev (1902, p. 489), the Ural and Siberian 

 stenoscismataceans fall into two distinct groups : those with the stolid- 

 ium present, and those with it absent. His conclusion was the same as 

 that which I derived from study of representatives of the entire super- 

 family ; namely, that certain groups of stenoscismataceans lack the sto- 

 lidium, not through incomplete preservation but because the shell was 



