Synthesis of the mesoglea by ectoderm and endoderm in reassembled hydra.

The structure and synthesis of the mesoglea was investigated in "reassembled" hydra-hydra regenerating from ectoderm and endoderm previously isolated from each other and then recombined. During tissue isolation and reassembly the mesoglea remains attached to the endoderm. It is observed to be quite elastic and resilient.

The influences of ecto- and endoderm in determining the axial polarity ofHydra attenuata Pall. (Cnidaria, Hydrozoa).

Ectoderm and endoderm of the gastric column ofHydra attenuata Pall. were separated from each other and reassembled with either the same (controls) or opposite polar orientation. The controls always regenerated a head and basal disc according to the original polarity.