it is to a very pronounced taste for collecting that we must attribute this mania of piling up before the entrance of the bower white stones, shells, and small bones. (Fig. 25.) These objects are intended solely for the delight of these feathered artists. They are very careful also only to collect pieces which have been whitened and dried by the sun.[93] [93] Gould first accurately described the habits of the Bower-birds, _Proceed. Zool. Soc._; _London_, 1840, p. 94; also _Handbook to the Birds of Australia_ (1865), vol. i. pp. 444-461. See also Darwin's _Descent of Man_ (1881), pp. 381 and 413-414. Certain Humming-birds also, according to Gould, decorate their dwellings with great taste. "They instinctively fasten thereon," he stated, "beautiful pieces of flat lichen, the larger pieces in the middle, and the smaller on the part attached to the branch. Now and then a pretty feather is intertwined or fastened to the outer sides, the stem being always so placed that the feather stands out beyond the surface."[94] [94] Gould, _Introduction to the Trochilidae_, 1861, p. 19. _Dwellings woven of flexible substances._--In spite of their lack of skill and the inadequacy of their organs for this kind of work, Fish are not the most awkward architects. The species which construct nests for laying in are fairly numerous; the classical case of the Stickleback is always quoted, but this is not the only animal of its class to possess the secret of the manufacture of a shelter for its eggs. A fish of Java, the Gourami (_Osphronemus olfax_), establishes an ovoid nest with the leaves of aquatic plants woven together. It makes its work about the size of a fist, takes no rest until it is completed, and is able to finish it in five or six days. It is the male alone who weaves this dwelling; when it is ready a female comes to lay there, and generally fills it; it may contain from six hundred to a thousand eggs. [Illustration: FIG. 25.] In the sea of Sargasso lives a fish which has received the name of the _Antennarius marmoratus_. Its flattened and monstrous head gives it a strange aspect, and it is marbled with brown and yellow. These colours are those of the tufts of floating seaweed around it, and, thanks to this arrangement, it can easily hide itself amid them without being recognised from afar. This animal constructs for its offspring a fairly safe retreat. The materials which it employs are tufts of Sargasso so abundant in this portion of the Atlantic. It collects all the filaments, and unites them solidly by surrounding them with viscous mucus which it secretes and which hardens. When its work is sufficiently firm not to be destroyed by the waves it lays its eggs in it, and the floating nest is abandoned to its fate. The little ones come out and find within it a sufficient protection for their early age. These dwellings thus floating on the surface of the sea are rounded and about the size of a cocoa-nut.