The cotyledons of an unnamed species of Cassia (a large tree from S. Brazil) rose 31° in the course of 26 m. after the pulvini and the blades had both been rubbed during 1 m. with a twig; but when the blade alone was similarly rubbed the cotyledons rose only 8°. The remarkably long and narrow cotyledons, of a third unnamed species from S. Brazil, did not move when their blades were rubbed on six occasions with a pointed stick for 30 s. or for 1 m.; but when the pulvinus was rubbed and slightly pricked with a pin, the cotyledons rose in the course of a few minutes through an angle of 6°o. Several cotyledons of C. neglecta (likewise from S. Brazil) rose in from 5 m. to 15 m. to various angles between 16v and 34°, after being rubbed during 1 m. with a twig. Their sensitiveness is retained to a somewhat advanced age, for the cotyledons of a little plant of C. neglecta, 34 days old and bearing three true leaves, rose when lightly pinched between the finger and thumb. Some seedlings were exposed for 30 m. to a wind (temp. 50° F.) sufficiently strong to keep the cotyledons vibrating, but this to our surprise did not cause any movement. The cotyledons of four seedlings of the Indian C. glauca were either rubbed with a thin twig for 2 m. or were lightly pinched: one rose 34°; a second only 6°; a third 13°; and a fourth 17°. A cotyledon of C. florida similarly treated rose 9°; one of C. corymbosa rose 7½°, and one of the very distinct C. mimosoides only 6°. Those of C. pubescens did not appear to be in the least sensitive; nor were those of C. nodosa, but these latter are rather thick and fleshy, and do not rise at night or go to sleep. Smithia sensitiva.—This plant belongs to a distinct sub-order of the Leguminosae from Cassia. Both cotyledons of an oldish seedling, with the first true leaf partially unfolded, were rubbed for 1 m. with a fine twig, and in 5 m. each rose 32°; they remained in this position for 15 m., but when looked at again 40 m. after the rubbing, each had fallen 14°. Both cotyledons of another and younger seedling were lightly rubbed in the same manner for 1 m., and after an interval of 32 m. each had risen 30°. They were hardly at all sensitive to a fine jet of water. The cotyledons of S. Pfundii, an African water plant, are thick and fleshy; they are not sensitive and do not go to sleep. Mimosa pudica and albida.—The blades of several cotyledons of both these plants were rubbed or slightly scratched with a needle during 1 m. or 2 m.; but they did not move in the least. When, however, the pulvini of six cotyledons of M. pudica were thus scratched, two of them were slightly raised. In these two cases perhaps the pulvinus was accidentally pricked, for on pricking the pulvinus of another cotyledon it rose a little. It thus appears that the cotyledons of Mimosa are less sensitive than those of the previously mentioned plants.[29]