Mimulus luteus--the intercrossed plants are derived from a cross between two plants of the 8th self-fertilised generation. The self-fertilised plants belong to the 9th generation: 100 : 4 : 3. Eschscholtzia californica--the intercrossed and self-fertilised plants belong to the 2nd generation: 100 : 45 : 40. Dianthus caryophyllus--the intercrossed plants are derived from self-fertilised of the 3rd generation, crossed by intercrossed plants of the 3rd generation. The self-fertilised plants belong to the 4th generation: 100 : 45 : 33. Petunia violacea--the intercrossed and self-fertilised plants belong to the 5th generation: 100 : 54 : 46. NB.--In the above cases, excepting in that of Eschscholtzia, the plants derived from a cross with a fresh stock belong on the mother-side to the same stock with the intercrossed and self-fertilised plants, and to the corresponding generation. These cases show us how greatly superior in innate fertility the seedlings from plants self-fertilised or intercrossed for several generations and then crossed by a fresh stock are, in comparison with the seedlings from plants of the old stock, either intercrossed or self-fertilised for the same number of generations. The three lots of plants in each case were left freely exposed to the visits of insects, and their flowers without doubt were cross-fertilised by them. Table 9/E further shows us that in all four cases the intercrossed plants of the same stock still have a decided though small advantage in fertility over the self-fertilised plants. With respect to the state of the reproductive organs in the self-fertilised plants of Tables 9/D and 9/E, only a few observations were made. In the seventh and eighth generation of Ipomoea, the anthers in the flowers of the self-fertilised plants were plainly smaller than those in the flowers of the intercrossed plants. The tendency to sterility in these same plants was also shown by the first-formed flowers, after they had been carefully fertilised, often dropping off, in the same manner as frequently occurs with hybrids. The flowers likewise tended to be monstrous. In the fourth generation of Petunia, the pollen produced by the self-fertilised and intercrossed plants was compared, and they were far more empty and shrivelled grains in the former. RELATIVE FERTILITY OF FLOWERS CROSSED WITH POLLEN FROM A DISTINCT PLANT AND WITH THEIR OWN POLLEN. THIS HEADING INCLUDES FLOWERS ON THE PARENT-PLANTS, AND ON THE CROSSED AND SELF-FERTILISED SEEDLINGS OF THE FIRST OR A SUCCEEDING GENERATION.