JO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



pressed tightly against brachial umbo ; slight constriction of postero- 

 lateral slopes. 



Brachial valve more strongly convex transversely and longitudi- 

 nally ; beak slightly attenuate, apex within pedicle valve. 



Pedicle valve interior with thick dental plates forming deep spondyl- 

 ium ; dental plates becoming thinner anteriorly ; spondylium elevated 

 on comparatively high median septum duplex, extending anteriorly 

 about one-third length of valve. 



Brachial valve interior with strong hinge plate, fimbriate knoblike 

 cardinal process at apex, crura extending from anterior edge ; camaro- 

 phorium formed by spreading of upper edges of high median septum 

 duplex, apparently in contact with hinge plate at posterior, extending 

 anteriorly about one-third length of valve, reaching slightly farther 

 anterior than spondylium; intercamarophorial plate thick, duplex, 

 propping underside of hinge plate from median line of camarophorium, 

 extending anteriorly farther than edge of hinge plate ; muscle and pal- 

 lial marks not observed. 



Types.— Uolotype: USNM 127876; Paratype: US NM 63169. 



Occurrence. — Trogkofel beds at Teufelsschlucht, near Neumarktl, 

 Yugoslavia (Permian; Artinskian according to Gignoux, 1955, p. 

 228). 



Comparisons. — Camerisma sagmaria is characterized by its rela- 

 tively small size, fold that is high at the anterior commissure but not 

 set off from the flanks by a break in lateral slopes, and its weak (barely 

 perceptible on some specimens) costae that split symmetrically. It is 



ABC D 



Fig. 13. — Camerisma sagmaria n. sp., Trogkofelschichten, Neumarktl, Yugo- 

 slavia, transverse sections X5, original length ca. 10 mm., USNM 63169, measure- 

 ments from pedicle valve beak. 



A. 0.5 mm. : thick shell shows wedged insertion of spondylium into valve floor ; 

 cardinal process fimbriate. B. 1.5 mm.: edges of camarophorium meet hinge 

 plate, intercamarophorial plate thick. C. 2.1 mm. : intercamarophorial plate dis- 

 tinct. D. 2.5 mm. : crura show anterior to hinge plate. 



