20 JURASSIC BIVALVIA AND GASTROPODA 



Bourguetia saemanni (Oppel) 

 Pietteia dusseensis sp. nov. 

 Ampullospira dejanira (d'Orbigny) 

 Globularia phasianelloides (d'Orbigny) 

 Nerinella cutleri sp. nov. 



Species known to occur in Europe in beds belonging to the same stage predominate 

 in these Oxfordian assemblages. The number of forms described as new is not large, 

 and previously described species known only from East Africa consist merely of 

 Grammatodon (Indogrammatodon) stockleyi, Trigonia (Frenguelliella) tealei and 

 Astarte huralensis. Species common to East Africa and India but unknown from 

 Europe are Grammatodon (Indogrammatodon) virgatus, Astarte sow erby ana, Eopecten 

 aubryi, Gryphaea hennigi and Stegoconcha gmuelleri. The subgenus Indogramma- 

 todon continues to be well represented. 



Kimmeridgian Assemblages 



In the area of southern Tanganyika dealt with in his memoir Aitken (1961 : 24-31) 

 distinguishes between the Septarian Marl, yielding Lower Kimmeridgian ammonites 

 (perhaps also Upper Oxfordian ones at the base of the formation) and the Tendaguru 

 Series, the lower part of which is classified as Middle-Upper Kimmeridgian and the 

 upper part as Upper Kimmeridgian-Tithonian. Aitken (1961 : 29) suggests that the 

 marine beds at Tendaguru itself all belong to the last of these divisions. 



The same worker (1961 : 25-26) has compiled a list of bivalves found in the 

 Septarian Marl based on the records of German workers. No specimens from this 

 formation have been examined in the course of the present work. He has also 

 recorded six named species and a number of forms identified only generically from 

 his Middle-Upper Kimmeridgian division of the Tendaguru Series. No bivalves 

 from this division have been examined in the course of the present work, but the 

 following gastropods from Dr. Aitken's collection are described : 



Bathrotomaria aitkeni sp. nov. 



Lissochilus stremmei Dietrich 



Pseudomelania vittata (Phillips) 



Pseudomelania (Oonia) aitkeni sp. nov. 



Globularia aff. phasianelloides (d'Orbigny) 



Pseudonerinea clio (d'Orbigny) 



Nerinella mandawaensis sp. nov. 



The presence of Pseudonerinea clio at this horizon is in keeping with its known 

 occurrences in Europe, but the presence of Pseudomelania vittata, a Cornbrash species 

 in Europe, in the Kimmeridgian of East Africa, is worthy of comment. As now 

 suggested in the discussion of this species, it is, however, possible that the distinc- 

 tions drawn between it and certain related but supposedly distinct species by 

 European workers are of no significance. 



The following is a combined list of the species now recorded from the " Upper 

 Kimmeridgian-Tithonian " division of Aitken's Tendaguru Series in the Mandawa- 





