82 JURASSIC BIVALVIA AND GASTROPODA 



relative size of the depressed ante-carinal space in the right valve. Except in very 

 early growth stages the rather irregular ribs cross this space and terminate at or very 

 close to the blunt marginal carina. The species appears to be more closely related 

 to the typical species of Opisthotrigonia than to Laevitrigonia. 



Superfamily MODIOMORPHACEA 



Family HIPPOPODIIDAE nov. 



Genus HIPPOPODIUM J. Sowerby 1819 



Hippopodium quenstedti (Dietrich) 



1933. Epihippopodium quenstedti Dietrich : 71, pi. 9, fig. 136 ; pi. 10, figs. 142, 143. 



Material. Six specimens. 



Localities and horizons, i mile N.W. of Tendaguru hill, Tanganyika ; Upper 

 Kimmeridgian, Nerinella Bed. Kindope road, Tingutitinguti creek, and i\ miles 

 N.N.W. of Tapaira, all near Tendaguru, Tanganyika ; Upper Kimmeridgian, 

 " Trigonia smeei " Bed. 



Remarks. Although Dietrich founded a genus Epihippopodium on this species, 

 comparison of his figures showing the internal characters of the shell and of the 

 present specimens with examples of Hippopodium ponderosum J. Sowerby, the 

 Lower Liassic type-species of Hippopodium, shows such close agreement in all 

 essential characters that the generic separation of the Tendaguru form seems un- 

 justified. H. quenstedti differs from H. ponderosum only in its larger size and its 

 broader form. It would thus seem that Hippopodium lingered on in some remote 

 area after its disappearance from N.W. Europe at the close of the Middle Lias, to re- 

 appear almost at the top of the Jurassic in East Africa. 



Superfamily CRASSATELLACEA 



Family ASTARTIDAE d'Orbigny 1844 



Genus AST ARTE J. Sowerby 1816 



Astarte lurida J. Sowerby 

 PI. 12, fig. 8 



1816a. Astarte lurida J. Sowerby : 81, pi. 137, fig. 1. 



1836. Astarte subtetragona Miinster [previously nom. nud.] ; Roemer : 113. 



Astarte excavata Sow. ; Goldfuss : 190, pi. 134, figs. 6c, d (non a, b) (non J. Sowerby). 



Astarte subcarinata Miinster in Goldfuss : 190, pi. 134, figs, ja, b. 



1837 

 1837 

 1840 

 1842 



1853 

 1869 

 1874 



Astarte subtetragona Miinster 

 Astarte subtetragona Miinster 

 Astarte subtetragona Miinster 

 Astarte subtetragona Miinster 

 Astarte subtetragona Miinster 



Goldfuss : 304 (Verbesserung, for pi. 134, figs. 6c, d.). 



Roemer : 13. 



Chapuis & Dewalque : 150, pi. 22, fig. 4. 



Brauns : 226. 



Dumortier : 176, pi. 40, figs. 5, 6. 



