. Animal studies. THE SIMPLEST ANIMALS OR PROTOZOA 27 Slipper Animalcule (Paramecium, Fig. 9), abundant in stagnant water. In this form the cuticle surrounding the somewhat cylindrical body is perforated by a great number of minute openings through which the internal protoplasm projects in the form of delicate threads. Each process, termed a ciliam, works on the same principle as the nagellum, but it beats with an almost perfect rhythm and in unison with its fellows, drives the an- imal hither and thither with considera- ble rapidity. On one side of the body is a furrow which deepens as it run
. Animal studies. THE SIMPLEST ANIMALS OR PROTOZOA 27 Slipper Animalcule (Paramecium, Fig. 9), abundant in stagnant water. In this form the cuticle surrounding the somewhat cylindrical body is perforated by a great number of minute openings through which the internal protoplasm projects in the form of delicate threads. Each process, termed a ciliam, works on the same principle as the nagellum, but it beats with an almost perfect rhythm and in unison with its fellows, drives the an- imal hither and thither with considera- ble rapidity. On one side of the body is a furrow which deepens as it runs backward and finally passes into the gullet (#), which leads into the interior of the body. Throughout the entire extent it is lined with cilia which create strong currents in the surrounding water and in this way conduct food down the guLet into the body. Embedded in the outer sur- face of the body, in among the cilia, are also a number of very minute sacks, each containing a coiled thread which may be discharged against the body of any intruder, so that this form is sup- plied with actual organs of defense. Two pulsating vacuoles () or simple kidneys are also present, consisting of a central reservoir into which a number of radiating canals extend. 28. The Bell Animalcule and other species.—The Bell Animalcule ( Vorti- cella, Eig. 10) is often found in the same situations as the Slipper Animalcule, which in certain respects it resembles. It is generally attached by a slender stalk, and where many. Fig. 10.— Vorticetta, an at- tached ciliate infusori- an. highly magnified, a, fully extended individ- ual ; , pulsating va- cuole ; g, gullet; n, nu- cleus, b, contracted specimen, c, small free- swimming individual, which unites with a sta- tionary individual (one partly united is shown in specimen b).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illust
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