Observations on the ephippia of certain maerothricid cladocerans

Ephippia of four maerothricid cladocerans are described, that of Opbryoxus gracilis (perhaps the most primitive anomopod ephippium) for the first time. All are attached to substrata, but each in a different way, in a manner that must inhibit rather than encourage dispersal. Notwithstanding the drought-resistant properties of the eggs of at least two of these species, it has evidently been a more successful evolutionary stratagem to ensure continuity of an already established colony than to face the hazards of dispersal in the dried condition. Although proven only for Streblocerus serricaudatus it is almost certain that drying of the resting eggs is not obligatory before hatching for any of these species. Hatching of the resting eggs of S. serricaudatus and Acantholeberis curvirostris is described.