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THIRD DIVISION OF ZOOLOGY;
REPRESENTATIVES OF THE FOUR ORDERS OF THE REPTILE RACE. — The Lizard; the Fresh. water Terrapin, or Turtle; the Adder; and a South American Frog, with“ horned eyelids."
LESSON I.-INTRODUCTORY VIEW: 1. The two divisions of animal life already described in the Third and Fourth Readers embrace the Mammalia and the Birds, which are called the warm-blooded Vertebrates, because they have warm blood, and a jointed back-bone or spinal column. The third division, which is composed of the REPTILES, and the fourth, which is composed of the FISHES, embrace the cold-blooded Vertebrates, which are so called because a spinal column, more or less apparent,2 is found in all of them, and their natural temperature, although
their blood is red, is but little, if at all, above that of the atmosphere or water in which they dwell. To our touch they appear decidedly cold. In this and a few succeeding lessons we are to treat of Herpetology, or the natural history of reptiles.
2. “It can not be denied,” says Swainson, “ that the form which nature has assumed in this division of animal life is associated in most minds with deformity or with horror. Yet, however the bulk of mankind may turn with disgust from the contemplation of these creatures, the philosophic observer, who knows that every thing which has proceeded from the hand of Omnipotence is, in its kind, good and perfect, will patiently investigate their history, and will endeavor to illustrate, in these despised and repulsive animals, those sublime truths of UNITY OF Plan, which are as perfect and apparent in the character of a loathsome reptile as in the formation of a Paradise-bird."
3. The skeleton of reptiles presents much greater variations in structures than are found in the warm-blooded vertebrates. Indeed, all the parts of which the skeleton of reptiles is composed, excepting the head and the vertebrated column and ribs, are wanting in one or another group; yet in such of the bones as are found we may trace a striking resemblance to the corresponding bones of mammalia and birds. Throughout all the divisions of animal life the changes of form are very gradual.
4. Although reptiles, with the exception of amphibians during a part of their existence, breathe by means of lungs, their circulating apparatus is not so perfect as in the mammalia and birds; for although the heart, in all but the amphibians, has two auricles, it has but one ventricle, 8 into which both of the auricles open, and where the pure and impure blood are mingled, and then sent in part to the lungs, and in part to the body. The veins and arteries of reptiles, therefore, are not filled with pure red blood, like those of the mammalia and birds, but with an imperfect fluid not so well adapted to give them a high degree of life and vigor. Hence, as the animal heat is always in proportion to the quantity of respiration—to the amount of oxygen or fuel consumed reptiles are comparatively cold blooded. Their lungs are small; their circulation is slow; and as they consume less air than the mammalia, they are capable of living for a longer time without it.
5. In all cold-blooded animals, the vital principle is much
stronger than in those whose blood is warm. Their heart pulsates, in some cases, for many hours after it has been removed from the body; the tortoise will continue to live, and exhibit voluntary motion, for a considerable time after having lost its head. The physiologist Lewes affirms that a frog moved about voluntarily the day after he had removed its brain; and one was kept alive forty days after having been subjected to the total deprivation of its lungs. As might be expected from the character of their blood, its slow circulation, and the smallness of the brain, reptiles are in general sluggish and indolent in their habits of life, and obtuse in their sensations; and in cold countries they pass a great part of the winter in a dormant 10 state. Almost all reptiles are carnivorous.11 They produce their young from eggs, which they generally deposit in warm sandy places, leaving them to be hatched by the warmth of the atmosphere,
6. The class of reptiles has been divided, by most naturalists, into the following four orders: first, the Chelonians, or tortoises; second, the Saurians, or lizards, which embrace the crocodiles; third, the Ophidians, or serpents; and fourth, the Amphibians, which embrace the frogs, toads, salaman. ders, and sirens—animals which undergo a wonderful transformation12 at a certain period of their lives, from the nature and habits of fishes to those of the true land reptiles. Think not that the study of the nature, character, and habits of such creatures is unworthy the human intellect: they form links in the great chain of animated nature; and the great whole of this most interesting portion of God's creation can not be understood without a knowledge of the parts of which it is composed. We may well apply to this subject Pope's celebrated lines
" From Nature's chain, whatever link you strike,
Tenth or ten thousandth, breaks the chain alike." 1 VËR'-TE-BRĀTE, an animal having a spine which receives the blood from the lungs 01 with joints.
See Fourth Reader, p. 49. 2 AP-PÁR'-ENT, easily seen; obvious. 8 VĚN'-TRI-ELE, a cavity of the heart which 3 TĚM'-PER-A-TŪRE, state of a body with-re- propels the blood to the lungs or arteries. gard to heat or cold.
See Fourth Reader, p. 49. 4 IN-VĚs'-TI-GĀTE, examine into.
9 OB-TŪSE', dull; not having acute sensi 5 STRƯ€T'-ŪRE, form, make, construction. bility. 6 AM-PHĪB'-1-ANS, see page 72.
10 Dór'-MANT, sleeping; not active. 7 AU'-RI-CLE, one of the cavities of the heart 11 €ÄR-NİY'-0-ROUS, feeding on flesh
112 TRANS-FORM-A'TION, change of form,
LESSON II.-A LETTER ABOUT THE CHELONIANS." “What do you think of turtles'?” Such was the question asked me by a young friend and former pupil of mine, then on a visit with me to our great metropolis, as, stepping out of a dining-saloon in Broadway, we stopped a moment to look at three enormous living sea-turtles that had just been deposited on the sidewalk from a dray-cart, with their backs downward to prevent them from running away. After some comments upon turtle-soup and aldermanic dinners, my young friend remarked that he knew very little about the better portion of the turtle family, and had a prejudice against the. whole race: he had seen, he said, great numbers of ugly-looking mud-turtles in swamps and river-marshes, and he thought these reptiles were very well adapted, by their disagreeable appearance, to the places which they inhabit. With a promise to give my friend some account, by letter, of the turtle portion of the class of reptiles, we parted; and now I proceed to make good my promise.
Dellwild, May 15th, 18—. 1. MY YOUNG FRIEND,-I begin this letter by recalling to your remembrance the substance of the remark which you made at our parting, “ that turtles are peculiarly adapted to certain unpleasant localities which Nature seems to have set apart for them.”. A fit starting-place is this; for here, by your own admission, is a beautiful harmony in nature, which would not be if the loveliest of singing-birds inhabited the marshes, and turtles, lizards, and crocodiles crawled in our gardens. The same kind of harmony will be found to exist throughout earth, air, and water: the eagle and the condor naturally betake themselves to mountain heights far from the dwellings of man; gaudy sun-birds and delicate hummingbirds
The crimson blossoms of the coral-tree
the lion for the forests, the tiger for the jungles, the fishes for the waters, and why not reptiles to crawl upon the earth, and turtles to wallow in the marshes? You may lay it down as a principle to begin with, that the harmony3 of nature would be incomplete if every nook of creation were not filled with its appropriate inhabitants.
2. But perhaps it may serve to give these lowly creatures
a greater degree of importance in your estimation, and dignify the study of their character and habits, to learn (if you are ignorant of it) that the celebrated naturalists Agassiz has devoted the greater part of one of his folio volumes upon the Natural History of the Animals of this Country to the subject of tortoises alone, and that he has filled the greater part of another volume with exquisite drawings of these animals. Do you think it was time wasted on his part? or that the cause of science will not be benefited by his labors ? Not content with information at second-hand, he has examined hundreds, and probably thousands, of the living animals themselves, and from his own personal knowledge has written his descriptions and made his drawings.
3. “Surely,” you say, “he must have traveled much, and waded through swamps and marshes innumerable, to have found so many of these disgusting animals!" By no means. Breaking in upon the natural harmony to which we have alluded, he had his garden full of them in the city of Cambridge, near Boston; and there he walked among them daily, fed them, and studied their character and habits. “But,” you ask, “how did he obtain them'?” Scientific men from all parts of our country collected them for him, and sent them to him. Thus Agassiz tells us that a gentleman of Natchez, Mississippi, not satisfied with collecting, extensively, the turtles in the neighborhood of his residence, undertook a journey of many hundred miles for the special purpose of securing all the species living in the adjoining regions, and, having completed the survey, set out with a cargo of living turtles, and brought them safely alive to him in Cambridge, after a journey of over a thousand miles.
4. I think you will agree with me that if such a man as Agassiz, whose name is every where honored for his contributions to science, devotes so much time to the study of tortoises, and publishes costly books to explain their structure and describe their habits, it is surely not unworthy a student's ambition to learn something about these animals, and the position which they occupy in the kingdom of animated nature. You will doubtless admit that it is
desirable, to say the least, in an age when natural history is receiving so much attention, to have some general knowledge of all its great divisions, that of herpetology among the rest, that you may not be wholly ignorant of what the learned are so much interested in.
5. Let me remind you of another advantage which will be