Different conchostracans from the 'Miembro Medio' of the Polar Formation (Upper Carboniferous-? Lower Permian) and of the Peine Formation (?Upper Permian) are described. They comprise: Cyzicus (Euestheria) cf. aricensis (Jones) from the former, and Palaeolimnadiopsis sp., Cornia sp., Estheriina (Estheriina) sp., Palaeolimnadia (Grandilimnadia) herbstin. sp.. Cyclestherioides (Cyclestherioides?) sp., Cyzicus (Euestheria) covacevichi n. sp., Cyzicus (Euestheria?) sp., Cyzicus (Lioestheria?) sp. and Asmussia sp. from the latter. Reference is made to previous studies and a brief outline of the general geology and the position of the fossiliferous levels in the sequences are also given. Finally, a few remarks on the geographical distribution and the biochrons of the described taxa from the southern hemisphere are made.