Euryleptidae, [19]
Eurythoe, [318]
Eustrongylus gigas, [142];
E. tubifex, [142]
Eusyllis, reproduction of, [278]
Excretion, as cause of colour, [291]
Excretory system, of Leptoplana, [13];
of Polyclads, [25];
of Triclads, [41];
absent in Acoela, [42];