416 MOLLUSCA SUB-KINGDOM VI 
Tivela, Link. Hinge with supplementary cardinals. Miocene to Recent. 

Fic. 760. ; 
MiG. 761. 
Meretrix semisulcata, Lam. Eo- acs : ; ¥ on ; ¢ 
cene ; Grignon, near Paris. Meretrix incrassata, Sow. Oligocene; Weinheim, near Alzey. 
Db. 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, no 
laterals, and deep pallial sinus. Cretaceous to Recent ; 
about 150 living species. 

Fic. 763. 
Cin ce 2B UMA Gs, T ; Danie Fic. 764. 
Hoernes. Miocene; Tapes gregaria, Partsch. Ae 
Enzesfeld, near Sarmatian Stage; Wiesen, ; Tapes (Baroda) fragilis, VOrb. sp. Upper 
Vienna. near Vienna. Cretaceous ; Gosau, Austria. 
Of the numerous sub-genera Baroda (Fig. 764) and Jscanotia (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 
Lipy Se Y Tapes in having a very short pallial sinus, 
tts SSS and the anterior adductor scar bounded by 
a ridge. Miocene brackish water-beds. 
‘ err = Venerupis, Lam. Cardinal teeth 2:2-3, 
Goines Escanotia) impar, Zitt. Upper Cretaceous; strong ; a borer or nestler, often deformed. 
Tertiary and Recent. 
d. Gemma, Desh.; Parastarte, Conr.; Pseplhis, Carp. Minute shells. Eocene to 
Recent. 

SS 
Fie. 765. 
