. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . etal. (2000: 11) for forms coiled in a loose helix and with an upward curving aperture. Thusas far as coiling is concerned, Cirroceras is very close if not indistinguishable fromD. (Eodidymoceras). The main differences are that in Cirroceras, of the two rows oftubercles, those of the lower row are larger, and constrictions are absent. In addition,Cirroceras is only known with certainty from the upper part of the upper Campanian. IfCirroceras is to be considered a valid taxon, it should possibly be regarded as a subg

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. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . etal. (2000: 11) for forms coiled in a loose helix and with an upward curving aperture. Thusas far as coiling is concerned, Cirroceras is very close if not indistinguishable fromD. (Eodidymoceras). The main differences are that in Cirroceras, of the two rows oftubercles, those of the lower row are larger, and constrictions are absent. In addition,Cirroceras is only known with certainty from the upper part of the upper Campanian. IfCirroceras is to be considered a valid taxon, it should possibly be regarded as a subgenusof Didymoceras. It is possibly derived from the D. (Eodidymoceras) lineage. Unfortunately our material is limited, but all three KwaZulu and Madagascan speciesto be described below show distinct Allocrioceras-like features, thus suggesting that theorigins of the Nostoceratidae may be sought in that genus. Occurrence Lower Campanian of KwaZulu; middle Campanian of Madagascar; ?middle and upperCampanian of the Western Interior. 292 ANNALS OF THE SOUTH AFRICAN MUSEUM. 4* i ,

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