I determined on this occasion to avoid the error of using pollen of not quite equal maturity for crossing and self-fertilisation; so that I squeezed pollen out of the conjoined anthers of young flowers for both operations. Several flowers on the crossed plant in Pot 1 in Table 5/70 were again crossed with pollen from a distinct plant. Several other flowers on the self-fertilised plant in the same pot were again self-fertilised with pollen from the anthers of other flowers on the SAME PLANT. Therefore the degree of self-fertilisation was not quite so close as in the last generation, in which pollen from the SAME FLOWER, kept in paper, was used. These two lots of seeds were thinly sown on opposite sides of nine pots; and the young seedlings were thinned, an equal number of nearly as possible the same age being left on the two sides. In the spring of the following year (1870), when the seedlings had grown to a considerable size, they were measured to the tips of their leaves; and the twenty-three crossed plants averaged 14.04 inches in height, whilst the twenty-three self-fertilised seedlings were 13.54 inches; or as 100 to 96. In the summer of the same year several of these plants flowered, the crossed and self-fertilised plants flowering almost simultaneously, and all the flower-stems were measured. Those produced by eleven of the crossed plants averaged 30.71 inches, and those by nine of the self-fertilised plants 29.43 inches in height; or as 100 to 96. The plants in these nine pots, after they had flowered, were repotted without being disturbed in much larger pots; and in the following year, 1871, all flowered freely; but they had grown into such an entangled mass, that the separate plants on each side could no longer be distinguished. Accordingly three or four of the tallest flower-stems on each side of each pot were measured; and the measurements in Table 5/71 are, I think, more trustworthy than the previous ones, from being more numerous, and from the plants being well established and growing vigorously. The average height of the thirty-four tallest flower-stems on the twenty-three crossed plants is 29.82 inches, and that of the same number of flower-stems on the same number of self-fertilised plants is 27.10 inches, or as 100 to 91. So that the crossed plants now showed a decided advantage over their self-fertilised opponents. 22. POLEMONIACEAE.--Nemophila insignis.