244 Annals of the South African Museum. 



of the terminal folioles, the short and simple lateral lobe, aud the 

 beginning development of adventitious lobes. 



Barroisiceras includes shells (e.g. B. desmouUnsi, Grossouvre sp.) 

 that are near the new genus in external shape, though less so in 

 suture-line, aud these forms with persistent keel, at any rate, may 

 have to be excluded from Barroisiceras, since the typical group of this 

 genus develops a concave periphery. 



Tissotidae have a pseudoceratitic suture-line, quite different from 

 that of the genus here described, though certain forms, e. g. Meta- 

 tissotia fourneli, Bayle sp., somewhat resemble it in external shape. 

 The earlier Psendotissotidae have a less simplified suture-line, but 

 cannot have given rise to a highly ornamented descendant in the 

 Senonian such as the form here described. 



Derivation from the main stock of the normally-lobed Prionotro- 

 pidae, through Pseudoschloenbachia, is most probable, and it seems that 

 whereas Diaziceras is nearer to the ancestral Psendoscliloenbacliia in 

 ornamentation, Splieniscoceras and Eidophoceras are, perhaps, closer to 

 it' in suture-line. It might be advisable to retain Hyatt's family 

 Eulophoceratidae for these four genera, all presumably of Campanian 

 age, but though there is a certain family resemblance with the suture- 

 lines of Eulophoceras&ud Spheniscoceras (cf. Fig. C la) and less so with 

 Psendoscliloenbachia, the similarity of the suture-line of Diaziceras 

 with those of Lenticeras, Paralenticeras and other pre-Campauiau 

 genera makes it doubtful whether in the present state of our know- 

 ledge a subdivision of the Seuouian Prionotropidae can yet be 

 attempted. Moreover, an undescribed form, closely resembling 

 "Barroisiceras naberfellneri '" from Madagascar, as figured by Boule, 

 Lemoiue aud Tlu'veniu,* but possibly nearer to the Upper Chico 

 " Schloenbachia " chicoensis, Trask sp. (Audersouf) occurs in Pondoland, 

 associated with many Campauian species, but also with " Puzosia " 

 sugata, Forbes sp., which occurs in the Lower Chico Beds of California, 

 and in Lower and Upper Senouian beds in India and elsewhere. 

 The likeness of these presumed Campaniau forms with Barroisiceras 

 may only be accidental, and since the median row of ventral tubercles 

 in the new Pondoland form is very high and acute, it may well be 

 assumed to lead from e. g. Muniericeras to Pseiidoschloenbachia and 

 Diaziceras. On the other hand, it looks as though a revision of 

 the many forms of " Schloenbachia " in the Lower and Upper Chico 

 Beds were most likely to throw light on the possible connec- 

 tion between Diaziceras and Barroisiceras on the one hand, and 



* Loc. cit. ii (1907), p. 43, pi. xi, fig. 3. 

 f Loc. cit. (1902), p. 116, pi. ii, fi<?s. 23-25. 



