The splendid plant _Rhodymenia palmata_, with its finely-coloured, semi-transparent fronds, is also recommended. It is the Dulse, or Dellis, eaten by the inhabitants of our northern coasts as a delicacy. Another species of _R. lacinata_ is represented to the left of Plate V., the transparent light-crimson fronds of which are excessively beautiful. Mr. Gosse tells us that the _Rhodymenia palmata_ is not suited to an Aquarium, because it appears to require the motion of the sea, and soon begins to decay in still water. If that be the case, let us provide a remedy, for the plant is one of the most beautiful among all its lovely congeners. When a plant of the gigantic lily of the Amazon river was first introduced, it refused to flower in the tank provided for its northern home, at the Duke of Devonshire’s residence at Chatsworth. But Sir Joseph Paxton, who then directed the floricultural operations of that magnificent abode, was not discouraged; and, seeking to impart to the still water of the tank something of the motion of a deep and majestic river, he contrived that a small but continuous stream should enter at one end of the tank, and, as it entered, turn a small paddle-wheel, the action of which imparted a gentle, undulating motion to the water of the whole tank. The device was triumphant, and the glorious _Victoria regia_ formed and expanded its giant flowers in the house which its curator had constructed for it, the plan of which eventually suggested the creation of the “Crystal Palace.” Let us not despair, therefore, of cultivating successfully the beautiful _Rhodymenia palmata_ in our Aquaria. The construction of a suitable apparatus for imparting motion to the too still waters, will form a pleasant _passetemps_ for some of our fair admirers of the pursuits of the Aquarium; and their success would be a signal triumph. But at present the beautiful red weeds, in general, are difficult of cultivation, and when they begin to exhibit spots of orange—a vegetable plague-spot not to be mistaken—it is a symptom of decay which should at once cause their removal from the Aquarium, before their decomposition leads to further mischief. The common Coralline, _Corallina officinalis_, of which a small spray is represented in the extreme lower part of Plate V., near the centre, is the “arboret of jointed stone” alluded to by the poet, and is well suited to Aquaria, thriving with little trouble. The smaller and slenderer kind is also suitable; but care must be taken, in collecting, not to choose the detached white fragments, which are washed up with every tide, for they are only the skeletons of the plant. It is the rosy-tinted specimens, verging to violet and purple, and still attached to pieces of rock, that are alone fit to remove to the Aquarium. [Illustration: PLATE I. 1. Delesseria sanguinea. 2. Punctaria latifolia. 3. Chordaria flagelliformis. 4. Vaucheria submarina. 5. Hildenbrandtia rubra.]