Identifier: introductiontozo00dave Title: Introduction to zoology; a guide to the study of animals, for the use of secondary schools; Year: 1900 (1900s) Authors: Davenport, Charles Benedict, 1866-1944 Davenport, Gertrude Anna Crotty, 1866- Subjects: Zoology Publisher: New York, Macmillan company London, Macmillian and co., ltd. Contributing Library: MBLWHOI Library Digitizing Sponsor: MBLWHOI Library

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Text Appearing Before Image: c-.vac FIG. 2S. —Eiif/lena viriilis, a lash-animalcule. A-D, four views illustratingthe characteristic movements; E and //, enlarged views of adult; F, out-line of anterior end further enlarged ; G, resting stage ; cy, cyst; .//, liagel-huu; m, mouth; nu, nucleus; w, gullet; pg, pigment spot; /•, reservoir.After Kent and Klebs. ~~| organism, half animal and halfplant, and forming a sort of con-necting link between the Pro-tozoa (or one-celled animals) andthe multicellular higher organ-isms. Volvox occurs abundantlyin our ponds and gets its namefrom its manner of revolving in FIG. 209. -- Volvox globator. t]ie water (Fig. 209).Much magnified. Photo. Y, .••.•••. £ of the living animal. Very different in habitat irom

Text Appearing After Image: 1 From volvere, to roll. THE PAEAMECIUM AND ITS ALLIES 227 the foregoing are the Sporozoa,1 which are minute rod-like organisms, occurring as parasites in the body ofvarious kinds of higher animals, especially in the food-tract. They increase by transverse division of their rod-like bodies; but periodically they encyst, and divide intonumerous spores, which, under favorable conditions, areset free in great numbers.

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