The cotyledons of Avena, like those of Phalaris, when growing in soft, damp, fine sand, leave an open crescentric furrow on the shaded side, after bending to a lateral light; and they become bowed beneath the surface at a depth to which, as we know, light cannot penetrate.  The arcs of the chords of the buried bowed portions formed in two cases angles of 20o and 21o with the perpendicular.  The open furrows on the shaded side were, in four cases, .008, .016, .024, and .024 of an inch in breadth.  Brassica oleracea (Common Red).—­It will here be shown that the upper half of the hypocotyl of the cabbage, when illuminated by a lateral light, determines the curvature of the lower half.  It is necessary to experimentise on young seedlings about half an inch or rather less in height, for when grown to an inch and upwards the basal part ceases to bend.  We first tried painting the hypocotyls with Indian ink, or cutting off their summits for various lengths; but these experiments are not worth giving, though they confirm, as far as they can be trusted, the results of the following ones.  These were made by folding gold-beaters’ skin once round the upper halves of young hypocotyls, and painting it thickly with Indian ink or with black grease.  As a control experiment, the same transparent skin, left unpainted, was folded round the upper halves of 12 hypocotyls; and these all became greatly curved to the light, excepting one, which was only moderately curved.  Twenty other young hypocotyls had the skin round their upper halves painted, whilst their lower halves were left quite uncovered.  These seedlings were then exposed, generally for between 7 and 8 h., in a box blackened within and open in front, either before a south-west window or a paraffin lamp.  This exposure was amply sufficient, as was shown by the strongly-marked heliotropism of all the free seedlings in the same pots; nevertheless, some were left exposed to the light for a much longer time.  Of the 20 hypocotyls thus treated, 14 remained quite upright, and 6 became slightly bowed to the light; but 2 of these latter cases were not really [page 480] exceptions, for on removing the skin the paint was found imperfect and was penetrated by many small transparent spaces on the side which faced the light.  Moreover, in two other cases the painted skin did not extend quite halfway down the hypocotyl.  Although there was a wonderful contrast in the several pots between these 20 hypocotyls and the other many free seedlings, which were all greatly bowed down to their bases in the direction of the light, some being almost prostrate on the ground.