Pseudohastigerina micra is hispid on the earliest parts of the last whorl: this is a feature common to the Globigerinaceae, and is distinct from Nonion, which is also clearly distinguished by its microgranular wall structure. An ancestral form to Pseudohastigerina may prove to be Protelphidium Haynes (1956, pp. 86 87). but the aperture is not adequately enough known in this genus to enable its relationships to be ascertained; Haynes (1956. pl. 16. fig. 9) illustrates the type species. P. hofkeri, as having a Nonion-like aperture without portici. Nonion sublaeve ten Dam, placed by Haynes in Protelphidium (op. cit., p. 87), seems unrelated to Pseudohastigerina.
Pseudohastigerina differs from Hastigerina by its true planispiral coiling throughout ontogeny, and by its possession of apertural portici.

Occurrence. Nonion micrus was first recorded from the Guayabal Formation of Mexico by Cote (1927, p. 22); he considered that this was probably equivalent to the Upper Claiborne, and is probably Middle Eoccnc in age. This species has been recorded sub- sequently from the higher parts of the Lower Eocene to the top of the Upper Eocene (e.g. Hornibrook 1958, pp. 29. 34 [as 'Globigerinella' iota (Finlay)]; Bolli 1957. p. 161: Subbotina 1953, p. 88; &c.). Bykova (1953. p. 86) has recorded G. micra (Cole) from beds in the Tadjikstan depression, which arc probably of Upper Palaeocene age; her specimen was not illustrated, however, and her determination cannot be checked. G. naguewichiensis Myatliuk probably belongs to this genus. but its age is not well known; Myatliuk (1950, p. 281) thought it to be possibly Oligocene. No species referable to this genus have been recorded from beds of other than Palaeogene age. Specimens of 'G. aspera (Ehrenberg) ', recorded by Haynes (1956, p. 98) from the Palaeocene Thanet Beds of East Kent, may prove to belong to Pseudohastigerina; his specimens require further study, but they may confirm the suspected Palaeocenc occurrence of this genus.

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