Tkigonarca tkkjl'etka Ccmrad p. 402 



16. Tile iiilenial cast of a riglii valve, showing ihe imiiression 



of the hinge. 



Cliff iK',-i:ul clay: Cliffwond P,iiiit. (1S5). 



Tricoxarca ci.ii'i'woiiUEXSis n. sp p. 401 



17. The iiilenial cast of a left \'al\'e, the type specimen. 



Cliff-a-o.id clay: Cliffwotid f"iiil. irSji). 



Tkigon,\rc.\ cl'NKU'Ormis C( mrarl p. 403 



18. The internal cast ')f a right \'al\e, (.xi). 



H'li, idhiiry clay: iicai- Matai>.\iii , I 10^). 

 ig-20. E.xteriial ami internal \ie\\s of a perfect right vaKe, ( X/') . 

 ( .\fter W'hitlielil. ) 



H'oiulhiiry clay: I laddonficld . irSj). 



Breviakc \ s.M-FoRin ( (.ia1)li 1 p. 404 



21-24. \ ie\vs of temr <lilfercnt inlenial ca~ts ef single \"alves. 

 iroadhnry clay: l.urUlard. (/02). 



BrEVI.\RCA Ct'NE.\T.\ ( Gahh) ]1. 406 



27. \'ieu' of the internal ca^t of a left \al\e. 



U'liadhiiry clay: l.unllard. iioj). 



NEMa.\RC-\ CRETACF.A Conrad p. 413 



2^. The internal cast of a right \-al\"e, 



U'andl'ury clay: l.urUlard. uoj). 

 26. The internal ca^t of a right N'alve. 



!\Ici-cliantz'illc clav-iiiarl : near Malaicair l/oi). 



042 



