Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . Vesicular airsacs. Fig. 234.—Respiratory apparatus of the Nepa cinerea. riously modified in the different families, to protect them fromthe entrance of foreign bodies. The abdominal segments ofthe body exhibit rythmic contractions and expansions during:respiration, which are well seen in the dragon-fly, and resem-ble the muscular movements of the thorax and abdomen duringthe same act in the pulmonated vertebrates.—T. W.] KESPIRATlOTf. 220
Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . Vesicular airsacs. Fig. 234.—Respiratory apparatus of the Nepa cinerea. riously modified in the different families, to protect them fromthe entrance of foreign bodies. The abdominal segments ofthe body exhibit rythmic contractions and expansions during:respiration, which are well seen in the dragon-fly, and resem-ble the muscular movements of the thorax and abdomen duringthe same act in the pulmonated vertebrates.—T. W.] KESPIRATlOTf. 220 § 386. In the lower vertebrata provided with 1 rings the/ form a single or- gan Luii;:. t Lungs but in thehigher classesthey are in pairs,placed in thecavity formedby the ribs, oneon each side ofthe vertebral co-lumn, and en-closing the heartbetween them(fig. 235). Thelungs communi-cate with theatmosphere bymeans of a tube,composedpf car-tilaginous rings,arising at theback part ofthe mouth, anddividing below, first into a branch for each organ, and then into innumerablebranches penetrating their whole mass, and finally terminatingin minute cells. This tube is the trachea (/), and its branchesare the bronchi. In the higher air-breathing animals the lungsand heart occupy an apartment by themselves, the chest (), which is separated from the other contents of the lowerarch of the vertebral column by a fleshy partition, called thediaphragm (fig. 180), passing across the cavity of the body,and arching into the chest. The only access to this apartmentfrom without is by the glottis through the trachea (fig. 235, t).§ 386*. The mechanism of respiration by lungs may becomp
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1870
