Animal and vegetable physiology, considered with reference to natural theology, by Peter Mark Roget .. . ecurity against injurious impressionsfrom without, with the most extensive powers oflocomotion; and which also admits of the fullest 300 THi: iMECHAMCAL FUNCTIONS. exercise of all those faculties of active enjoymentwhich are characteristic of animal life. She hasprovided for the first of these objects by en-closing the softer organs in dense and hornycoverings, which perform the office of an ex-ternal skeleton, sustaining and protecting theviscera, and furnishing extensive surfaces ofattach
Animal and vegetable physiology, considered with reference to natural theology, by Peter Mark Roget .. . ecurity against injurious impressionsfrom without, with the most extensive powers oflocomotion; and which also admits of the fullest 300 THi: iMECHAMCAL FUNCTIONS. exercise of all those faculties of active enjoymentwhich are characteristic of animal life. She hasprovided for the first of these objects by en-closing the softer organs in dense and hornycoverings, which perform the office of an ex-ternal skeleton, sustaining and protecting theviscera, and furnishing extensive surfaces ofattachment to the muscles, from the action ofwhich all the varied movements of the systemare derived. The muscular system of perfect insects is ex-ceedingly complex. Lyonet has described anddelineated an immense number of muscularbands in the caterpillar of the Cossus, and theplates he has given have been copied in a va-riety of books in illustration of this part of thestructure of insects. The recent work of StrausDurckheim aftbrds an equally striking exampleof admirable arrangement in the muscles of the. Melolontha vulgaris, or cockchaffer, the ana-tomy of which has been minutely investigated by WINGED INSECTS. 301 that distinguished entomologist. These musclesare represented in Fig. 144, which has beencarefully reduced from his beautifully executedplates. The largest mass of muscular fibres isthat marked a, which depress the wings, andare of enormous size and strength. On examining the different structures whichcompose the solid frame-work of insects, we findthem conforming in every instance to the ge-neral type of annulose animals, inasmuch asthey consist of thickened portions of integu-ment, encircling the body; but variously unitedand consolidated, for the manifest purpose ofobtaining greater mechanical strength and elas-ticity than if they had remained detached pieces,joined only by membranous connexions. A longflexible body, such as that possessed by the My-riapoda, could not
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Keywords: ., bookcentury18, booksubjectnaturaltheology, booksubjectphysiology
