Corynida

Corynida, an order of the Hydroid Zoophytes or Hydroidea (q.v.). The members of this order are compound and form either plant-like or encrusting colonies. They form a skeleton or polypary, which is usually a simple chitinous membrane around the base and stems of the colony: in Tabularia, a common British example, the skeleton is a thin perisarc of chitin and forms a tube as far as the base of the polypes. In some the skeleton is calcareous as in some Hydractiniae, and in the extinct genus Parkeria. The latter is a common fossil in the Cambridge Greensand, and occurs as spherical masses ranging up to two inches in diameter. It was once regarded as one of the arenaceous Foraminifera (q.v.), but is now usually placed in this group. Hydractinia is an encrusting form, and is composed of a series of layers separated by pillars. The genus began a little before the time of the Chalk, and is still living; it is the earliest of the Corynida, as the Palecozoic forms once referred to it are now known to belong elsewhere. Thus the Carboniferous Palaecoryne is part of a Bryozoan. The Corynida are all marine.