. Elementary zoology. Zoology. 376 ELEMENTARY ZOOLOGY raise and lower. These movements, together with the contraction of the diaphragm, cause the expansion and contraction of the thoracic cavity whereby the lungs are regularly filled and emptied. Note that the abdomen is covered by a double layer of mus- cular tissue, the outer part made up of the external oblique muscles, the inner by the internal oblique muscles. Examine the heart. How many auricles has it ? The ventricles in the mouse, as in the bird, are entirely separated, forming twro complete compartments, a right and a left ventricle.
. Elementary zoology. Zoology. 376 ELEMENTARY ZOOLOGY raise and lower. These movements, together with the contraction of the diaphragm, cause the expansion and contraction of the thoracic cavity whereby the lungs are regularly filled and emptied. Note that the abdomen is covered by a double layer of mus- cular tissue, the outer part made up of the external oblique muscles, the inner by the internal oblique muscles. Examine the heart. How many auricles has it ? The ventricles in the mouse, as in the bird, are entirely separated, forming twro complete compartments, a right and a left ventricle. The blood flowing from the veins of the body is collected in the right auricle, thence it passes into the right ventricle, wdience it is con- Fig. 148.—Diagram of veyed to the lungs ; returning it flows through the left auricle into the left ventricle, whence it is forced through the arteries of the body. For a study of the circulatory system in the arrows show the di- , /r oX , , . rection of the current; mammals (fig. 148), a rat or a rabbit the shaded vessels should be injected by the teacher and carrv venous blood, the others arterial blood, an advanced text-book, as Parker s (From Kingsley.) t, Zootomy '' or Marshall and Hurst's " Practical Zoology," used as a guide. A sheep's heart is very good to cut open for a class demonstration. Make a drawing of the organs observed thus far in the dissection. The kidneys in the mouse are situated in the dorsal region next to the backbone. They consist of two bean- shaped smooth glands. From them a pair of ducts, the uretersy can be traced down to a median thin-walled. the circulation of the blood in a mammal; a, auricles ; /, lung ; tv, liver; p, portal vein bringing blood from the intestine; v. ventricles;. 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 wor
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1902
