ORDER IV TELOTREMATA 325 
Crura very long, ventrally curved. Median septum of dorsal valve faint. 
Jura; Sicily and the Alps. 
Dimerella, Zittel. Small plicate shells with a high umbo and a straight 

Fie. 544. 
A, Rhynchonella — vespertilio, 
Brocchi. Upper Cretaceous ; 
Villedieu, Touraine. 1/;. B, R. 
A, Rhynchonella lozia, Fisch. Upper Jura; Moscow. a, », Profile lacunosa, Schloth. sp. Upper 
and dorsal view, 1/; ; c¢, Cast; d, Anterior view. B, R. quadriplicata, Jura; Engelhardsberg, Franconia. 
Quenst. Middle Jura; Bopfingen, Wiirtemberg. Interior of dorsal valve. 
hinge-line. Delthyrium large, with linear deltidial plates. Dorsal valve 
with a high median septum extending to the ventral valve. Alpine Trias. 
Peregrinella, Oehlert. Large, strongly plicate Rhynchonellae without fold 
or sinus. Cardinal area well 
developed. Cretaceous; 
Europe. 
Hemithyris, VOrb. (Fig. 
545). Smooth or faintly 
plicate Lhynchonellae with a 
high ventral beak and open 
delthyrium. No dental fe cede 
Lanhee ROG 4 canthothyt is spinosa, 
plates. Recent. Schloth. sp. Middle 
ie ‘ Hemithyris psittacea, Lam.sp. Recents Jura; Auerbach,Upper 
Frieleia, Dall. Resem- Mediterranean. My. Palatinate. 

Fic. 546. 
bling Hemithyris, but with a 
small dorsal spondylium. Recent ; American Pacific. 
Acanthothyris, VOrb. (Fig. 546). Like the last, but with well-developed 
dental plates, and the exterior surface covered with spines. Jura to Recent ; 
Europe and Japanese Province. 
Cryptopora, Jeffreys (Atretia, Jeffreys ; Neatretia, Oehlert). Small smooth 
shells with an acute and prominent open ventral beak. Dental plates and 
a high, mesially situated, dorsal septum present. Recent. 
Cyclorhina, Hall and Clarke. Devonian ; North America. 
Superfamily 2. TEREBRATULACEA. Waagen. 
Derived Telotremata with the brachia supported by calcareous, primitive, or meta- 
morphosed loops. Devonian to Recent. ‘ 
