94 JURASSIC BIVALVIA AND GASTROPODA 



its posterior extremity. Although species of Coelastarte are well known to be vari- 

 able, it seems desirable to regard the East African form as a separate species. 



Genus PRAECONIA Stoliczka 1871 

 Praeconia rhomboidalis (Phillips) 



1829. Isocardia rhomboidalis Phillips : 128, pi. 3, fig. 28. 



1934a. Praeconia rhomboidalis (Phillips) ; Arkell : 251, pi. 33, figs. 14, 15. 



1948. Praeconia rhomboidalis (Phillips) ; Cox & Arkell : 28. 



Material. One specimen (no. LL. 35124), ex B.P. Coll. 



Locality and horizon. Hill-top N. of Lugoba on road to Msata, Tanganyika ; 

 Callovian(P). 



Remarks. This specimen consists only of the posterior half of one valve, but is 

 an unmistakable representative of the species, the geological range of which in Europe 

 is from Bajocian to Oxfordian. 



Genus SEEBACHIA Holub & Neumayr 1882 

 Seebachia janenschi Dietrich 

 1933. Seebachia janenschi Dietrich : 43, pi. 4, figs. 57, 63, 64 ; pi. 5, figs. 67, 73. 



Material. Two specimens (including no. LL.35125), ex B.P. Coll. 



Locality and horizon. Mpilepile stream, 800 yards E.N.E. of junction of main 

 road and Mahokondo road, Mitole, northern Mandawa area, Tanganyika ; Upper 

 Kimmeridgian. 



Remarks. These specimens, which are preserved in a coarse conglomerate, are 

 eroded, but have the unmistakable outline of B. janenschi. The larger is 52 mm. 

 long. The type locality of the species is Tendaguru, where it occurs in the " Trigonia 

 smeei " Bed. 



Superfamily LUGINACEA 



Family LUCINIDAE Fleming 1828 



Genus LUC IN A Bruguiere 1787 



Lucina sp. 



PI. 15, figs. 5a, b 



Material. Four internal moulds (nos. LL.35047-50). 



Locality and horizon. Didimtu hill, 2 miles S. of Bur Mayo, N.E. Kenya ; 

 Upper Lias, Toarcian, Didimtu Beds. 



Description. Of medium size (length of largest specimen c. 22 mm.), suborbi- 

 cular with a hexagonal tendency, length and height almost equal, umbones angular, 



