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Show 101 l\1EANS OF EXPRESSION CHAP. lV. utterances after a time becoming through habit in~ tinctive. In this manner actions performed by the contraction of voluntary muscles might have been combined for the same special purpose with those effected by involuntary muscles. It is even possible that ani1nals, when excited and dimly conscious of some change in the state of their hair, might act on it by repeated exertions of their attention a11d will ; for we have reason to believe that the will is able to influence in an obscure manner the action of some unstriped or involuntary muscles, as in the period of the peristaltic movements of the intestines, and in the contraction of the bladder. Nor must we overlook the part which variation and natural selection may have played; for the males which succeeded in makjng themselves appear the most terrible to their rivals, or to their other enemies, if not of overwhelming power, will on an average have left mqre offspring to inherit their characteristic qualities, whatever these 1nay be and however first acquired, than have other males. The inflation of the body, and other means of exciting fear in an enmny.-Certain Amphibians and Reptiles, which either have no spines to erect, or no muscles by which they can be erected, enlarge themselves when alarmed or angry by inhaling air. This is well known to be the caso with toads and frogs. The latter animal is made, in ~sop's fable of the 'Ox and the Frog,' to blow itself up from vanity and envy until it burst. This action must have been observed during the most ancient times, as, according to Mr. Hensleigh Wedgwood, 21 the word toad expresses in several of the languages of Europe the habit of swelling. It has been observed 21 'Dictionary of English Etymology,' p. 403. CHAP. 1 V. fN ANIMAL '. 105 wGi th some of tho xotic peci 1'n th zo 1 o"·l ·a 1 ardens ; ancl Dr. iinther believes that it is ge: ral th~·oughout the group. Judging from analogy, th pnmary purpose. probably wa to mak the body appear as largo and fnghtful as possible to an enemy; but an~th.er, and P<:rhaps more important secondary advanta~ e 1s thus g~n1e~. When frogs are seized by snakes, which are their chief enemies, they enlarge tb .mselv R wonderfully; so that if the snake be of small izc as Dr.. Gunther informs me, it cannot swallow the f1~og, wluch thus escapes being devoured. Chameleons and some other lizards inflate themsel vcs when angry. Thus a species inhabiting Oregon, the Tapa~a Douglasii, is slow in its movements and do 'H ~~~t bit~, b~t has a ferocious aspect; "when irritated " It ~pnngs 1n. a most threateni~g manner at anything ,, P?Inted at .It;. at the. same time opening its n1outh " Wide and hiSSing audibly, after which it inflates its body, and ~hows other marks of anger." 22 Sev~ra~ kinds of snakes likewise inflate them elvc. · ~v hen Irnta~ed. . The puff-adder (Clotho arietans) is Iemar~able In th1s respect; but I believe, after carefully watching these animals, that they do not act thus ~ r the .sake. of increasing their apparent bulk, but simply for In?~hng a large supply of air, so as to produce their ~urpns1ngly loud, harsh, and prolonged hissing sound. The Cobr~s-de-capello, when irritated, onlargo thems~ lves a httle, and hiss moderately; but, at the sam tim~ they lift their heads aloft, and dilate by means f the1r elongated anterior ribs, the skin on each ide of .the neck into a large flat disk,-the so-called hood. With their widely opened mouths, they then assumo a 22 c? the account of the ltn.bit!:l of this animal by Dr. 'oopcr, a~ quoted m 'Nature,' April 27, 1871, p. 512. |