ONE who has not studied living Foraminifera or Radiolaria can get only an inadequate conception of the remarkable activities exhibited by the delicate protoplasmic extensions that form in such protozoans the thread-like pseudopodia. The figures and descriptions in text-books of zoology, in Verworn's Physiology, in Biitschli's Protozoa, or in special monographs naturally fall short of complete expression of the changeableness as well as the extreme delicacy of certain of these processes, though they teach us that the sensitive, contractile, co6rdinating powers of protoplasm may here be expressed in filaments of exceeding tenuity and inconstancy of form and position,-in flowing, liquid, apparently homogeneous protoplasm. Such filose phenomena were practically unknown in Metazoa till a recent paperl described their occurrence in the eggs, polar bodies, blastulae, gastrulae, and larvae of certain. echinoderms. Here the cells put forth protoplasmic threads of excessive delicacy, that may branch and anastomose, elongate or shorten. By means of such filose processes the cells become connected amongst themselves, and, as these connections are living material comparable to the sensitive pseudopodia of many Protozoa, their importance in understanding the coordination of cells and their subordination to the entire mass, during the animals' development, was emphasized.1 Having been shown the filose threads in living starfish eggs, I have been able to observe the less attenuated ones present in