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Show 92 HABITS OF ·woRMS. CHAP. II. are led by instinct to plug up their burrows; and it might have been expected that they would have been led by instinct how best to act in each particular case, independently of inte1ligence. We see how difficult it is to judge whether intelligence comes into play, for even plants might sometimes be thoug~t to be thus directed; for instance wben displaced leaves re-direct their upper su:faces towards the light by extremely comphcated movmnents and by the shortest course. With animals, actions appearing due to intelligence may be performed through inherited h.a~it without any intelligence, although abonginally thus acquired. Or the habit ma_Y have been acquired through the preservatwn anll inheritance of beneficial variation8 of some other habit; and in this case the new habit will have been acquired independently of intelligence throug·hout the whole course of its development. There is no a priori improbability in worms having acquired special instincts through either of these two latter means. Nevertheless it is incredible that instincts should have been developed in reference to objects, such as the leaves or CnAP. II. THEIR INTELLIGENCE. 93 petioles of foreign plants, wholly unknown to the progenitors of the worms which act in the described manner. Nor are their action so unvarying or inevitable as are most true instincts. As worms are not guided by special instin~ ts in each particular case, though possessmg a general instinct to plug up their burrows, and as chance is excluded, the next most probable conclusion seems to be that they try in many different ways to draw in objects, and at last succeed in some one way. But it is surprising that an animal so low in the scale as a worm should have the c~pacit.y f~r acting in this manner., as many ~1g.her animals have no such capacity. For Instance, ants may be seen vajnly trying to drag an object transversely to their cou:se, which could be easily drawn longitudinally; though after a time they generalJy act in a wiser manner. M. Fabre ~tates * that a Sphex-an insect belongIng to the same highly-endowed order with ants-stocks its nest with paralysed * See his interesting work, 'Souvenir::; entomolocriqucs '1879 pp. lGS-177. 0 I ' |