part, that is in a direction opposite to the dependent tip, in the same
manner as occurred with the hypocotyl of the cabbage. Another buried and
arched epicotyl was observed in the same manner, excepting that the two
legs of the arch were tied together with fine silk for the sake of
preventing the great movement just mentioned. It moved, however, in the
evening in the same direction as before, but the line followed was not so
straight. During the morning the tied arch moved in an irregularly
circular, strongly zigzag course, and to a greater distance than in the
previous case, as was shown in a tracing, magnified 18 times. The movements
of a young plant bearing a few leaves and of a mature plant, will hereafter
be described.

Fig. 16. Tropaeolum minus (?): circumnutation of buried and arched
epicotyl, traced on a horizontal glass, from 9.20 A.M. to 8.15 P.M.
Movement of bead of filament magnified 27 times.
[page 28]

Citrus aurantium (Orange) (Aurantiaceae).--The cotyledons are hypogean. The
circumnutation of an epicotyl, which at the close of our observations was
.59 of an inch (15 mm.) in height above the ground, is shown in the annexed
figure (Fig. 17), as observed during a period of 44 h. 40 m.

Fig. 17. Citrus aurantium: circumnutation of epicotyl with a filament fixed
transversely near its apex, traced on a horizontal glass, from 12.13 P.M.
on Feb. 20th to 8.55 A.M. on 22nd. The movement of the bead of the filament
was at first magnified 21 times, or 10 1/2, in figure here given, and
afterwards 36 times, or 18 as here given; seedling illuminated from above.

Aesculus hippocastanum (Hippocastaneae).--Germinating seeds were placed in
a tin box, kept moist internally, with a sloping bank of damp argillaceous