A word commonly employed in connection with the lower forms of marine life also requires some passing notice. The term _zoophyte_, derived from two Greek words signifying respectively _animal_ and _plant_, would seem appropriate enough in describing generally many of the organisms found in the great deep. But the term as now used signifies an animal, and nothing but one, however plant‐like it may appear. The simplest forms of marine animal life are found in the extensive group known as the Protozoa. Varied as they are, they may be generally described as devoid of articulate skeleton, or nervous system; they are animals, a large part of them microscopic, with a vegetative existence. “In their obscure and blind life,” says Figuier, “have they consciousness or instinct? Do they know what takes place at the three‐thousandth part of an inch from their microscopic bodies? To the Creator alone does the knowledge of this mystery belong.” The limits of this work preclude the possibility of details. To the division Protozoa belong the sponges, already described, the Rhizopods (_Rhizopoda_), _root‐footed_ animals, and the _Infusoria_, animalcules so small that a drop of water may contain millions. The Rhizopods are found both in fresh and salt water, but the marine forms are by far the more numerous. They are simply minute lumps of diaphanous jelly, the quantity of matter in them being so infinitesimal, and their transparency so great, that the eye, assisted by the powers of the microscope, can only take cognisance of them by the most careful arrangement of light. But for all that, they are known to have feet or feelers, to have digestive apparatus—some of them being, for their size, quite voracious feeders—which may be seen stuffed with microscopic _algæ_, or sea‐weeds. It is believed that they are multiplied by parting with portions of their bodies, which become separate beings.