HISTOLOGICAL FEATURES CORRELATED WITH GAS SECRETION IN HYDRA OLIGACTIS PALLAS

Abstract

The basal disc of hydra has a two-fold secretory function: (1) It secretes a mucus by means of which the polyp is anchored. (2) It secretes gas that is retained within a wall of mucus by means of which the polyp is lifted to the surface of the water. This dual function of the basal disc places a peculiar metabolic demand upon the disc's endoderm, ectoderm and mesoglea. As a result of this peculiar metabolism and the conditions arising out of gas-secretion, the mesoglea becomes flooded with a plasma and thus handles either metabolic food or metabolic wastes in a manner that foreshadows the plasma of the circulatory media of triploblastic animals.