Abstract:
Morphological changes which occur during tentacle formation
have been described in the colonial athecate hydroid Cordylophora
lacustris. These changes involve an outpocketing of mesoglea into
a finger-like extension of the hydranth. Gastrodermal cells line the
inside of this extension of mesoglea while ectodermal cells cover the
outside. Electron micrographs reveal the presence of several distinct
cell types. Their function and possible role in tentacle differentiation
is discussed.