. Text book of zoology. Zoology. 488 Vertebrata. large intestine, tlie end portion alone being termed rectum. A c se c u m almost always arises from the large intestine at its junction with tlie small intestine; in some animals, {, the Horse), it attains an enormous length, whilst in others {, Man), it is small, or even rudimentary* The liver, which is situated behind the diaphragm, is usually, but not invariably, provided with a gall bladder (it is wanting in, , the Horse), The pancreas has generally one duct,t which opens into the anterior portion of the small intestine, either t
. Text book of zoology. Zoology. 488 Vertebrata. large intestine, tlie end portion alone being termed rectum. A c se c u m almost always arises from the large intestine at its junction with tlie small intestine; in some animals, {, the Horse), it attains an enormous length, whilst in others {, Man), it is small, or even rudimentary* The liver, which is situated behind the diaphragm, is usually, but not invariably, provided with a gall bladder (it is wanting in, , the Horse), The pancreas has generally one duct,t which opens into the anterior portion of the small intestine, either together with, or independently of, the bile duct. J Respiratory Organs. The entrance to the larynx is a longitudinal slit behind the tongue, anterior to the entrance into the oesophagus. In front of the opening, there is a peculiar flap, the epiglottis, which contains a large elastic cartilage; under ordinary conditions it is directed forwards, often reaching even up over the edge of the soft palate (Fig. 396), but when food passes from the mouth through the pharynx into the oesophagus, the epiglottis is let down over the glottis. The walls of the larynx are supported by large cartilages, viz., the cricoid behind, the large thyroid below; in front and above, the two arytenoids. The rest of the trachea is usually strengthened for some distance by cartilaginous rings; it branches posteriorly into two large bronchi, which branch again; each lung, as already stated, is an arboriform organ, of which both the larger and finer branches are hollow. Only the peripheral branches, which have thin walls, and are furnished with small dilations (alveoli) are respiratory; in other regions the tubes have thicker walls, provided in the larger branches with cartilaginous rings like those of the trachea, or with small cartilaginous plates. All the branches are held together by connective tissue. The lungs, with the heart, are situated in the anterior portion of the body-cavity, the thorax, along
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
