gently out of the water, without disturbing anything, and place it on the edge of my hand, which is simply moistened, so that it may not adhere too closely. I oblige it to contract more and more, and this also enlarges the stomach and mouth. The worm then is partly coming out of the mouth, and, keeping it open, I then take in my right hand a hog's bristle, rather thick and without a point, and I hold it as one holds a lancet for bleeding. I bring its thickest end to the hind end of the polype and push it, making it enter into its stomach, which is the more easily done as in that part it is empty and much enlarged. I push on the end of the hog's bristle, which continues to invest the polype. When it reaches the worm, which holds the mouth open, it either pushes the worm or passes by its side, and at last comes out by the mouth, the polype being thus completely turned inside out." [Illustration: HYDRA, WITH YOUNG ONES BUDDING OUT FROM ITS SIDE.] Very strange, indeed, to think that animals with the wrong side outermost should continue to eat, grow, and multiply, as Trembley assures us his specimens did, though, perhaps, we shall not wonder that they often tried to turn themselves back to their original condition, and with success, unless Trembley took steps to prevent them. There are other strange things recorded of the fresh-water polypes, as that different individuals can be grafted together without the slightest inconvenience to any of the parties, the joint-stock company of course being limited. The hydrae live on small worms, larvae of gnats, water-fleas, and other minute creatures; they catch them with their tentacles or fishing-lines, and draw them to the mouth. It is maintained by many observers, with good reason, that these arms have the power of paralysing, in an instant, the worms they wrap themselves round. There are at least three well-marked species of hydrae to be met with in the ponds and ditches of this country. There is the green hydra, the light flesh-coloured or common hydra, and the long-armed hydra, the most interesting of all. See, there is the water-primrose, now in flower, with its delicate pink corolla and bright orange centre. Let us gather a few plants, and then return home. [Illustration] FOOTNOTES: [Footnote B: 'Marvels of Pond Life,' by H. J. Slack, p. 92.] WALK V. MAY.