Note K — INTRODUCTION TO PART I.
Reading edition
Except in "Proterospongia," an organism of doubtful affinities but not a sponge. It consists of a mass of jelly containing ordinary cells, with collar-cells outside.
Reading edition
Except in "Proterospongia," an organism of doubtful affinities but not a sponge. It consists of a mass of jelly containing ordinary cells, with collar-cells outside.