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Show 20 IIABITS OF WORMS. CHAP. I. persons have found no difficulty in observing worms at night by the same means.* Hoffmeister, however, states t that wonns, with the exception of a few individuals, are extremely sensitive to light; but he admits that in most cases a certain time is requisite for its aetion. These statements led me to watch on many successive nights worms kept in pots, which were protected from currents of air by means of glass plates. The pots were approached very gently, in order that no vibration of the floor should be caused. When under these circumstances worms were illuminated by a bull's-eye lantern having slides of dark red and blue glass, which intercepted so much light that they could be seen only with some difficulty, they were not at all affected by this amount of light, however long they were exposed to it. The light, as far as I could judge, was brighter than that from the full moon. Its colour apparently made no difference in the result. When they were * :For instance, Mr. Bridgman and Mr. Newman (' 'l'hc Zoologist,' vol. vii. 1849, p. 2576), and some friends who observed worms for me. t 'Familie der Regenwtirmer,' 1845, p. 18. CHAP. I. THEIR SENSES. 21 illuminated by a candle, or even by a bright paraffin lamp, they were not usually affected at first. Nor were they when the light was alternately admitted and shut off. Sometimes, however, they behaved very differently, for as soon as the light fell on them, they withdrew into their burrows with almost instantaneous rapidity. This occurred perhaps once out of a dozen times. When they did not withdraw instantly, they often raised the anterior tapering ends of their bodies from the ground, as if their attention was aroused or as if surprise was felt; or they moved their bodies from side to side as if feeling for some object. They appeared distressed by the light ; but I doubt whether this was really the case, for on two occasions after withdrawing slowly, they remained for a long time with their anterior extremities protruding a little from the mouths of their burrows, in which position they were ready for instant and complete withdrawal. When the light from a candle was concentrated by means of a large lens on the anterior extremity, they generally withdrew instantly ; but this concentrated light failed |