CLASS II BRACHIOPODA 401 



beat, converging, and uniting in an elongate triangular plate, which on the 

 posterior margin gives off a small, posteriorly directed, rod-like process. 

 Hinge-plate large and often much thickened. Thick dental plates present. 

 Lower Devonian ; North America and Germany. 



Lissopleiira Whitfield. Strongly plicate Bensselaeriae, with the dental 

 plates uniting to form a short rostral cavity. Lower Devonian ; North 

 America. 



Beachia Hall and Clarke. Lentiform, finely striated Bensselaeriae with the 

 lateral margins of the valves inflected, the anterior plate of the brachidium 

 broader, and the rod-like process longer. Lower Devonian ; North America. 



Newherria Hall (Bensselandia Hall). Resembling Bensselaeria externally, 

 but without the stxdate surface. Interior strongly marked by muscular scars 

 and vascular sinuses. Devonian ; North America and Europe, 



Chascothyris and Denkmannia Holzapfel. Devonian ; Germany. 



OrisJcania Hall and Clarke. Large Centronellae with a continuous hinge- 

 plate bearing a thin vertical spur or cardinal process. Lower Devonian ; 

 North America. 



Selenella Hall and Clarke. Comprises biconvex terebratuliform shells 

 with a CentroneUa-like loop, but the triangular j^late not mesially thickened. 

 Devonian ; North America. 



Bomingerina Hall and Clarke. Small biconvex Centronellae with the 

 median ridge on the f^nterior plate of the loop elevated into a high vertical 

 lamella almost touching the ventral valve and extended both anteriorly 

 and posteriorly. Devonian to Lower Carboniferous ; North America. 



Trigeria (Bayle) Hall and Clarke. Plicated, plano-convex Centronellae. 

 Devonian ; France, Brazil and North America. 



(?) Scaphiocoelia Whitfield. Very large, plicate, piano- or concavo-convex, 

 Centronella-\ike shells exteriorly. Loop unknown. Shell substance fibrous, 

 impunctate. (?) Devonian ; South America. 



Juvavella Bittner. Small, smooth, biconvex shells, with a very short 

 Centronella-\ike loop. Alpine Trias. 



Juvavellina and Dinarella Bittner. Alpine Trias. Aspidothyris Diener. 

 Trias of India. 



Nudeatula Bittner. Like Juvavella, but having a longer loop with a well- 

 developed and fimbriated vertical median plate. Alpine Trias. 



Family 2. Stringocephalidae King. 



Specialised Devonian Terebratuloids with a long loop, following the margin of the 

 dorsal valve, and not recurved in front. Development direct. Probably no median 

 coiled arm. Shells smooth. Devonian. 



Stringocephalus Defr. (Fig. 597). This, the solitary genus of the family, is 

 limited to the Devonian of Europe and North America. 



Family 3. Terebratulidae Gray. 



Terebratuloids developing originally a Centronella-like loop, and thence by a short 

 series of metamorphoses resulting at maturity in a free loop of varying form 

 Devonian to Recent. 



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