REGENERATION OF COENOSARC FRAGMENTS REMOVED FROM THE STEM OF TUBULARIA CROCEA

¹ From the Department of Zoölogy, Columbia University, the Marine Biological Laboratory, Woods Hole, Mass., and Queens College, New York

The morphogenesis of coenosarc expressed from the perisarc of Tubularia stems is described. A series of structural changes occurs in the coenosarc, there being first a dedifferentiation of histological structure, followed by a redifferentiation culminating in the regeneration of new hydranths.

The gradient of oxygen consumption present in the stem of Tubularia disappears when the coenosarc is removed from the perisarc. This physiological dedifferentiation represents an increase as well as an equalization of oxygen consumption by coenosarc fragments from distal and proximal levels of the stem.

Concomitant with the morphological and physiological dedifferentiation, differences in the ability of distal and proximal levels of the stem to regenerate disappear. Distal and proximal coenosarc fragments regenerate at the same rate and develop similar types of polarity relationships.

The different kinds of regenerants obtained are described and classified on the basis of their polarity relationships. Evidences were given that these polarity relationships are new, and have no relation to the original polarity in the intact stem.

The value of using expressed coenosarc to study the effect of the environment on regeneration and on the origin of polarity in regeneration is discussed.