Animal life in the sea and on the land . The Circulation of Cold-blooded Animals.—The heartof the turtle contains three cavities, two auricles and aventricle. This formation of the heart gives to all reptiles a peculiar circula-tion which characterizes them as cold-blooded animals, and which is of somuch interest in this connection thatwe will try to understand it at once. 7. After the blood is purified in thelungs, it enters the left auricle (, b), while the impure blood from thebody enters the right auricle (a). Thepure blood from the left auricle, andthe impure blood from the right a
Animal life in the sea and on the land . The Circulation of Cold-blooded Animals.—The heartof the turtle contains three cavities, two auricles and aventricle. This formation of the heart gives to all reptiles a peculiar circula-tion which characterizes them as cold-blooded animals, and which is of somuch interest in this connection thatwe will try to understand it at once. 7. After the blood is purified in thelungs, it enters the left auricle (, b), while the impure blood from thebody enters the right auricle (a). Thepure blood from the left auricle, andthe impure blood from the right au-ricle, are then both poured into theventricle (c), and this mixed blood issent all over the system, as well as tothe lungs. This imperfect plan of cir-culation causes the low temperature, theslow breathing, and the sluggish habits of reptiles. Theirblood is not well supplied with oxygen, consequently it doesnot leap and bound through their veins as is the case withmore highly developed animals, tilling them with energyand Fig. 143. — Circula-tion in Reptiles. a, right auricle ; b, leftauricle; c, ventricle. 220 ANIMAL LIFE IN THE SEA AND ON THE LAND. 8. Land-turtles and Water - turtles. — Animals of thisspecies which live upon the land generally pass by thename of tortoises; they can swim, when there is occasionfor it, but their limbs are better fitted for walking. Tur-tles and terrapins, on the other hand, live in the wateror in marshy places, and their feet form good swimmingpaddles. 9. Supposed to Live to a Great Age.—It is supposed thattortoises live to be very old, and dates which are some-times found carved upon their shells might serve tostrengthen this impression; but we have no way of judg-ing of the correctness of these dates, and they may notbe reliable. Tortoises bearing some peculiar mark arefound repeatedly in the same locality, from which weinfer that they are not roving in their habits. 10. Hibernating.—None of the reptiles are fond of col
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1887
