. Zoölogy [microform] : descriptive and practical. Zoology; Zoologie. 202 Descriptive Zoology. i!. row, and continues back, as a transparent air sac, through most of the length of the body cavity. The left lung is rudimentary, sometimes being so small it is difficult to see. The windpipe is long, beginning very close to the front of the floor of the mouth. This is regarded as an adaptation to the mode of eating, so that the snake may not be suffo- cated during the long and tedious process of swallowing. Circulatory System. —The heart beat is slow and the circulation not very active. The heart
. Zoölogy [microform] : descriptive and practical. Zoology; Zoologie. 202 Descriptive Zoology. i!. row, and continues back, as a transparent air sac, through most of the length of the body cavity. The left lung is rudimentary, sometimes being so small it is difficult to see. The windpipe is long, beginning very close to the front of the floor of the mouth. This is regarded as an adaptation to the mode of eating, so that the snake may not be suffo- cated during the long and tedious process of swallowing. Circulatory System. —The heart beat is slow and the circulation not very active. The heart continues to beat long after the head is severed. The temperature of the blood varies with that of the surroundings. Excretory Organs. — In the posterior part of the body cavity are the two long, slender kidneys, whose ducts open into the cloaca. The Eggs and the Young. — Eggs are produced in two long, narrow ovaries; the oviducts also open into the cloaca. Some snakes deposit their eggs in the earth, though probably a majority bring forth the young alive. Senses of Snakes. — Sight and touch are fairly well de- veloped, though a study of snakes does not reveal a keen sense of sight. Some snakes are affected by music, show- ing a sense of hearing. Of their senses of smell and taste we know but little. Adaptations of Internal Organs to External Form. — We have seen how the external form is adapted to the mode of life. Let us now see how the internal organs are fitted to the necessarily long, narrow space allotted to them. In the first place the body cavity is so long chat a moderately long digestive tube is accommodated without the necessity of coiling it, as in many animals. But one lung is developed, and that one is long and narrow, whereas our bodies admit of two relatively wide lungs placed side by side. The liver. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance o
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1903
