CLASS I 



PELECYPODA 



4Ü5 



Fig. 810. 



Tcllina rostralina Desh. Eocene ; Damery, 

 near Epernay. 



Tellina plaiiata Lam. Miocene 

 near Vienna. 



Pötzleinsdorf, 



Fig. 817. 



Tellina (Linearia) biradiata Zittel. Upper 



Cretaceous ; Gosau, Austria. 



Family 34. Semelidae Dali. 



Resembling the Tellinidae, but with the resilium internal, often on a distinct chondro- 

 phore, and lüith the laterals, when present, stronger and less distant. Tertiary to Kecent. 



Semele Schiim. (Ämphidesma Lam.). Shells large, rounded, thick, often conspicu- 

 ously sculptiired ; 100 species. Tertiary and 

 Kecent. 



Cumingia Sow. Small, tliin, with a spoon- 

 like chondrophore ; habit nestling. Tertiary 

 and Recent. 



m-^^ 



Fig. 818. 



Ahra apelina (Ren.). Miocene ; Grund, 

 near Vienna. 



Scrohicularia Schum. Differs froni Semele in 

 having no lateral teeth. Tertiary and Recent. 



Ahra Leach (Syndosmya Recluz) (Fig. 818). 

 Smooth, small, thin ; cardinals 2:2, an anterior and posterior lateral present ; 

 chondrophore narrow, oblique, not separated from the hinge line. Tertiary and 

 Recent ; chiefly in deep water. 



Family 35. Psammobiidae Dali. 



Shell as in the Tellinidae, hut usually more 

 equivalve and less twisted, with more conspicuous 

 epidermis and nymphs, hroader hinge-plate, and 

 a wider posterior gape ; lateral laminae on the 



Fig. 819. 



Psammobia effiisa Desh. Eocene (Calcaire 

 Grossier) ; Farnes, 



• Fig. 820. 



Psammosolen (Macha) deshayesii (Desm. ). Calcaire 

 Grossier ; Grignon, near Paris, i/j. 



