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THE FRESH-WATER AQUARIUM.

the top of an arch, but not for the deep water of the tank. The plant is perennial and produces a white blossom, with one petal and four stamens. The flower-stem is velvety, and the leaves spread in a tuft from the root.

POTAMOGETON DENSUS.

Utricularia Vulgaris, or the hooded milfoil, may be recommended as a botanical curiosity, but is met with only (as far I know) in the brooks of the southern counties—Hants and Surrey especially. It produces a yellow blossom in June and July. The root has a curious inflated appendage. There are two other species, U. minor and U. intermedia, differing but little in general aspect from the common sort.