Cyst: A protective envelope formed around an organism during period of rest.
Cytode: The non-nucleated cell hypothecated by Haeckel.
Cyptoplasm: The cell-body or extranuclear protoplasm of a cell.
Endomixis: A process of nuclear reorganization among the protozoa, which does not require the coöperation of two cells as in conjugation (amphimixis).
Endoskeleton: An internal living skeleton providing support and protection (as well as organs of movement, in the bone-levers to which the muscles are attached)—it is characteristic of the vertebrates.
Enzymes: Organic catalysts, i. e., complex chemical substances formed by organisms and serving to accelerate chemical processes taking place in said organisms, e. g., the digestive enzymes, which accelerate the hydrolysis of starches, fats, and proteins.
Epigenesis: Development of the embryo by differentiation of previously undifferentiated protoplasm.
Fats: Esters of the higher fatty or organic acids (such as stearic, palmitic, and oleic) esterified with the trihydric alcohol glycerine (glycerol).
Gamete: A reproductive cell specialized for syngamy, i.e., for union with a complementary germ cell, their union giving rise to a synthetic cell known as a zygote.
Ganglion: An aggregate of nerve-cells consisting mainly of neural cell-bodies together with supporting cells.