In the Vertebrata, on the contrary, the skeleton being internal the external form depends almost entirely8 on the proportions and arrangement of that skeleton, which again is strictly9 adapted to the functions necessary for the well-being10 of the animal. The form cannot therefore be rapidly modified by variation, and the thin and flexible integument11 will not admit of the development of such strange protuberances as occur continually in insects. The number of species of each group in the same country is also comparatively small, and thus the chances of that first accidental resemblance which is necessary for natural selection to work upon are much diminished. We can hardly see the possibility of a mimicry by which the elk12 could escape from the wolf, or the buffalo13 from the tiger. There is, however, in one group of Vertebrata such a general similarity of form, that a very slight modification, if accompanied by identity of colour, would produce the necessary amount of resemblance; and at the same time there exist a number of species which it would be advantageous14 for others to resemble, since they are armed with the most fatal weapons of offence. We accordingly find that reptiles15 furnish us with a very remarkable16 and instructive case of true mimicry.

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1
varied
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| adj.多样的,多变化的 | |
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2
mimicry
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| n.(生物)拟态,模仿 | |
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enquire
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| v.打听,询问;调查,查问 | |
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deceptive
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| adj.骗人的,造成假象的,靠不住的 | |
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modifications
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| n.缓和( modification的名词复数 );限制;更改;改变 | |
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modification
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| n.修改,改进,缓和,减轻 | |
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7
interfering
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| adj. 妨碍的 动词interfere的现在分词 | |
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8
entirely
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| ad.全部地,完整地;完全地,彻底地 | |
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9
strictly
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| adv.严厉地,严格地;严密地 | |
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10
well-being
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| n.安康,安乐,幸福 | |
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11
integument
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| n.皮肤 | |
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12
elk
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| n.麋鹿 | |
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13
buffalo
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| n.(北美)野牛;(亚洲)水牛 | |
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advantageous
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| adj.有利的;有帮助的 | |
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reptiles
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| n.爬行动物,爬虫( reptile的名词复数 ) | |
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remarkable
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| adj.显著的,异常的,非凡的,值得注意的 | |
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