[Note on Medicago lupulina, communicated by Mr. Darwin:—]

“I covered a number of plants with a net (which I know does not injure their seeding), and left others close by uncovered, and these were visited incessantly by bees. I could not compare their relative fertility with accuracy, on account of the easy shedding of the seed; but I gathered 150 not quite ripe pods of both; those from under the net weighed 77 grains, and those visited by the bees weighed 101 grains. No doubt the difference in the weight of the seed would have been considerably greater, as the pod is formed independently of the number of seeds.”²