Tomasz Brzeziński

The embryonic stages of the anomopod Bosmina longirostris of the family Bosminidae were elucidated by scanning electron microscopy. Along with the corresponding stages of Bosmina coregoni described by Kotov (2001), these findings have enabled a comparison to Dunhevedia crassa , as a representative species of the family Chydoridae, and to Eurycercus lamellatus of the family Eurycercidae. In general, the developmental patterns are similar in these four species, particularly from blastulation to the first instar. The principal difference during embryogenesis is that in D. crassa and B. longirostris five thoracopods (six in E. lamellatus ) are differentiated already with endo- and exopodites.