THE LEUCOCYTES OF ARBACIA PUNCTULATA

Abstract

Two distinctive types of leucocytes, trephocytes and phagocytes, were found in Arbacia. Their morphology, function and development are outlined. The young oocytes take up corpuscular, nutrient matter derived from the trephocytes and possibly also echinochrome. The occurrence of respiratory pigments in trephocytes is discussed and the erythrocytes found to be a special kind of trephocytes. The phagocytes were observed to engulf and digest trephocytic material and also intact, living trephocytes, the latter phenomenon representing a case of cellular cannibalism. Additional instances of cellular cannibalism from invertebrates and vertebrates are brought forward. The findings are correlated with previous observations of the writer and his earlier thesis, viz.: that the animal cell, in addition to dissolved substances, takes up particulate cell material. This thesis is further extended to include cannibalism as an apparently normal and not infrequent mode of cellular nutrition.