820 L. F. Spatli — Jurassic A'lnmonites from East Africa. 



India and Madagascar, though the writer found closely comparable 

 ammonites in abundance in the Argovian beds of Jebel Zaghuan, 

 Tunis. ^ The first lateral saddle is trifid in this species as in the East 

 African specimen, but the simple folioles of the saddles represented 

 in the figures of Popovici-Hatzeg - and Prinz ^ are quite different. 

 On the other hand, it apj^ears that, as in the case of Ph. disputabile, 

 the many references to Ph. mediterraneum given in palaeontological 

 literature probably include a variety of evolute Phylloceras of the 

 idtramontanwn group, '' and of the Capitanei group in the case of 

 Ph. dispidahile. It has already been mentioned that though the 

 course of constrictions cannot accurately be determined, the specimen 

 under consideration probably belongs to this Capitanei assemblage. 



The rectangular section of the specimen here described might 

 suggest connexion with the genus Sowerhyceras. The suture-line, 

 however, is sufficiently distinct from that of this genus. 



Horizon and Distribution. — Phylloceras disputahile is a Bathonian 

 form, and occurs (generally associated with Ph. Kudernatschi, 

 Protetragonites tripartitum, etc.) in the South of France, the Italian 

 Alps, , at Swinitza in Hungary, in the Carpathians, the Caucasus. 

 It has also been recorded from the " Callovian " (zone of M. m.acro- 

 cephalus) of East Africa and India, and Haug ^ has it already in the 

 Bajocian (zones of " Sonninia" Romani and " Cosmoceras '' sub- 

 furcatum) of the South of France. 



Locality. — No. 10, from the grey, otherwise unfossiliferous lime- 

 stone beside the break-pressure tank, mile W on the Mombasa pipe- 

 line (together with Soiverbyceras sp. aff. tortisulcato d'Orbigny sp.). 



^ " Jurassic Ammonites from Jebel Zaghuan " • Q.J.G.S., vol. Ixix, 1913, 

 p. 561. 



^ Loc. cit., 1905, text-fig. 6 on p. 15. 



^ Loc. cit., 1904, pi. xxxvi, fig. 8. 



■* Hochstetter (loc. cit., ]). 142) states that P7i. mediterrmieum hegins in the 

 Klaus Beds and ranges into the Tithonian. This vertical range is unusually 

 great for a species group, even of a Phylloceras. 



5 Loc. cit., pp. 70, 73. 



{To he continued.) 



