The polyps of the madrepores resemble flowers when their upper disc is expanded and their feelers are out in the water. When contracted, they are concealed from sight in the calcareous cells, which have grown with themselves, and form part of the madrepora. These beautiful and curious natural productions assume many distinct forms. Some of them are arborescent, as in _Stylaster flabelliformis_, which puts forth a perfect forest of trunks and branches. Others are star‐like in shape; many are more or less cylindrical and oval, as in the well‐known “Brain coral” (_Meandrina cerebriformis_). Another genus is entitled _Fungia_, from a supposed resemblance to the mushroom, there being this difference between terrestrial and marine mushrooms—that the former have leaflets below, and the latter have them above. One of the most pleasing forms is found in the Plantain Madrepore, where the polyps are arranged in tufts. [Illustration: MADREPORES.] The Sea‐anemones (_Actinidæ_) will be now, thanks to the popularity of the aquarium, tolerably familiar to most readers. Although undoubtedly animal, they much more resemble flowers. They are to be found of the most brilliant colours and graceful forms. The body of the Sea‐anemone is “cylindrical in form, terminating beneath in a muscular disc, which is generally large and distinct, enabling them to cling vigorously to foreign bodies. It terminates above in an upper disc, bearing many rows of tentacles, which differ from each other only in their size. These tentacles are sometimes decorated with brilliant colours, forming a species of collar, consisting of contractile and sometimes retractile tubes, pierced at their points with an orifice, whence issue jets of water, which are ejected at the will of the animal. Arranged in circles, they are distributed with perfect regularity round a central mouth. These are their arms.” The stomach of the sea‐anemone is both the seat of digestion and of reproduction. The young are actually ejected from the mouth with the rejecta of their food. “The daisy‐like anemones in the Zoological Gardens of Paris,” Frédol tells us, “frequently throw up young ones, which are dispersed, and attach themselves to various parts of the aquarium, and finally become miniature anemones exactly like the parent. An actinia, which had taken a very copious repast, ejected a portion of it about twenty‐four hours later, and in the middle of the ejected food were found thirty‐eight young individuals.” According to one author, an accouchement is here a fit of indigestion! Sea‐anemones may be mutilated, cut limb from limb, or torn to pieces, and each piece will become a new anemone in the end. “They adhere,” says Dr. Johnson, “to rocks, shells, and other extraneous bodies by means of a glutinous secretion from their enlarged base, but they can leave their hold and remove to another station whensoever it pleases them, either by gliding