. The animans and man; an elementary textbook of zoology and human physiology. may be called the most imperfectmodes of locomotion are shown by the simplest modes we have already studied in Amoeba, Para-mcecium, and Vorticella. The living elements in the bodyof the higher animals are the many individual cells, and they show many kinds of move-ment. But motion in thehigher animals is producedchiefly by the contraction ofmuscles, each of which ismade up of contractile fibreswhich may be thought to bemodifications of such a fibreas exists in the stalk of Vor-ticella. The muscles req
. The animans and man; an elementary textbook of zoology and human physiology. may be called the most imperfectmodes of locomotion are shown by the simplest modes we have already studied in Amoeba, Para-mcecium, and Vorticella. The living elements in the bodyof the higher animals are the many individual cells, and they show many kinds of move-ment. But motion in thehigher animals is producedchiefly by the contraction ofmuscles, each of which ismade up of contractile fibreswhich may be thought to bemodifications of such a fibreas exists in the stalk of Vor-ticella. The muscles require firmpoints of attachment to pullFIG. 16. Diagram of cross-section against and the complex through the thorax of an insect movements of most animalsto show the exo-skeleton and the leg and wing muscles attaching require also rigid levers and to it; h, heart; al. c, alimentary fulcra. These firm solidcanal; v. n. c. ventral nerve cord; r • i> u ,J,, , , parts of an animals body w, wing; /, leg; m, muscles. r J (Much enlarged; after Graber.) COmpOSC its skeleton,
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Keywords: ., bookcentury1900, bookd, booksubjectphysiology, booksubjectzoology
