Threenew speciesofnummulites;Nummulitesminutussp.nov.,oNm. anensis sp.nov. andN.schaubisp.n ov., are described and illustrated from the Eocene of Northem Oman. N. omanensis sp. nov. and N. schaubi sp. nov. are shown to range from Early to Middle Lutetian whilstn]. minutus sp. nov. ranges from Late Ypresian to Early Lutetian. N. minutiis sp. nov. is far smaller in all major dimensions than any species of Nummulites previously described and if found in isolation would be assumed to be very primitive and probably dated as Late Palaeocene. However, N. minutus sp. nov. was found in association with an unreworked Lutetian fauna. The commonly held belief that proloculus size and test size are smallest in the most primitive (i.e. oldest) species must therefore be treated with some degree of caution.