COELOMIC CORPUSCLES OF ECHINODERMS

Abstract

1. The cellular elements from the body fluid of 15 different species of echinoderms were studied by phase contrast microscopy. Thirteen types of corpuscular elements were identified and the distribution, properties, characteristics and, where possible, functions, were determined. 2. Some types of coelomocytes were observed in the species examined here which had not been previously described, e.g. the red corpuscles of the sand dollar and crinoid, and the lobular corpuscles of the crinoid. Some of the coelomocytes formerly described were also found in the species described. Among these are the controversial bladder amebocytes in which the presence of bladder has been questioned. Present studies verify the bladders as real structures easily seen in three dimensions. The bladder amebocyte undergoes a transformation into the filiform amebocyte which represents a pre-coagulation change. 3. A greater diversity of cell types was observed in the body fluid of the more highly specialized forms such as the echinoids than in the less specialized asteroids.