416 MOLLUSCA SUB-KINGDOM vi 



Tivela, Link. Hinge with supplementary cardinals. Miocene to Recent. 



Meretrix semisulcata, Lam. Eo- 

 cene ; Grignon, near Paris. 



FIG. 7 

 Meretrix incrasmta, Sow. Oligocene ; Weinheim, near Alzey. . 



6. Circe, Schum. (Fig. 762). Umbones compressed, sculpture often divaricate, 

 ligament immersed. Tertiary and Recent. 



Sub-genus Gouldia, Adams. Small, concentrically striated. Eocene to Recent. 



Ptychomya, Agassiz. Cretaceous. 



c. Tapes, Megerle (Pullastra, Sow.), (Fig. 763). More or less elongate, oval, with 



narrow hinge plate, divergent and often bifid cardinals, 110 



laterals, and deep ^j^^fes. pallial sinus. Cretaceous to Recent ; 



about 150 living x^"*^"^^^ species. 



Circe ex i mi a, 

 Hoernes. Miocene ; 

 Enzesfeld, near 

 Vienna. 



FIG. 



Tapes gregaria, Partsch. 

 Sirmatian Stage ; Wiesen, 

 ear Vienna. 



Tapes (Baroda) fragilis, d'Orb. sp. 

 Cretaceous ; Gosau, Austria. 



Upper 



Of the numerous sub-genera Baroda (Fig. 764) and Iscanotia (Fig. 765), Stol., from the 



Cretaceous, are remarkable for their elonga- 

 tion and the ridge-like form of the posterior 

 cardinal. 



Oncophora, Rzehak. Differs from 

 Tapes in having a very short pallial sinus, 

 and the anterior adductor scar bounded by 

 a ridge. Miocene brackish water-beds. 



Venerupis, Lam. Cardinal teeth 2 : 2-3, 

 strong ; a borer or nestler, often deformed. 

 Tertiary and Recent. 



d. Gemma, Desk; Parastarte, Conr.; Psephis, Carp. Minute shells. Eocene to 

 Recent. 



Tapes (Iscanotia) impar, Zitt. 

 Gosau. 



Upper Cretaceous : 





