Cell Morphologies and Contacts in Annual Fish Embryos
During epiboly and early dispersed stages, the deep blastomeres of annual fish embryos emigrate from the blastodisc to wander as easily visible single cells in the narrow space between the yolk synctial layer (YSL) and the enveloping cell layer (ECL). Subsequently these deep blastomeres reaggregate and eventually form the definitive embryo. We are studying these morphogen-etic cell movements and the controls that may exist upon cell movement in vivo. Time-lapse cinemicrophotography showed three types of cell movement by the deep blastomeres during epiboly through reaggregation stages [1], The present electron microscopic investigation was undertaken to reveal further details of the intercellular contacts during these developmental stages.