. Elementary text-book of zoology. Zoology. •290 .MAMMALIA. Srd .h finally on the intercostal arteries and the iliac veins of the Dolphin. A renal-portal system is always absent. The lymphatic system is provided with numerous lymphatic glands, and its main trunk (dt ictus t-horacicus), which is placed on the left, opens into the superior vena cava. Of the so-called vascular glands the spleen, the thy- mus, and the thyroid, which is especially developed in the young, are very generally present (fig. 675). The paired lungs (tig. 675) are freely suspended in the thoracic cavity, and are dis- ting
. Elementary text-book of zoology. Zoology. •290 .MAMMALIA. Srd .h finally on the intercostal arteries and the iliac veins of the Dolphin. A renal-portal system is always absent. The lymphatic system is provided with numerous lymphatic glands, and its main trunk (dt ictus t-horacicus), which is placed on the left, opens into the superior vena cava. Of the so-called vascular glands the spleen, the thy- mus, and the thyroid, which is especially developed in the young, are very generally present (fig. 675). The paired lungs (tig. 675) are freely suspended in the thoracic cavity, and are dis- tinguished by the numerous ramifications of the bronchial tubes, the finest branches of which end with conical, fun- nel-shaped dilatations (///- fundibula), which are pro- vided on their lateral surfaces with swellings. Respiration is mainly effected by the movements of the diaphragm, which forms a complete, usually transversely placed, Fi. >. G7C. -Circulatory apparatus of Man (from Owen septum between the thoracic after Alien Thomson). TV, Right Ventricle; T'S, and abdominal cavities : by left Ventricle ; Ad, right Auricle ; As, left Auricle ; A o, Aortic arch;,4 o« f , ., , , pflfpct . ATT m i -n T> i • 7> OI DJie 11US ttlaU lltLVo ctll clltr^u pulmonary Vein ; Tr, Trachea ; Sr, Bronchi; I' Lungs ; L, .Liver; N, Kidney ; D, Intestine. in dilating the thorax. The trachea is, as a rule, straight, without coils, and divides at its lower end into two bronchi leading to the lungs. There may be, in addition, a small accessory bronchus on the right side. The trachea is supported by cartilaginous half-rings which are open behind, and only excep- tionally by complete rings of cartilage. The first part of the trachea,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Claus, Carl, 1835-1899; Sedgwick, Adam
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
