or mussels will live in confinement, and a few make an interesting addition to a collection. Water-snails act as scavengers for the under-water settlement, and a handful of them may be added to form a sort of street-cleaning department. Caddice worms and the little fresh-water shrimp which you find among the water-plants make excellent food for your fish. Avoid Salt-Water Sand, stones, and shells, for the salts they contain are injurious to fresh-water creatures. Do not change the water in the tank after it is in running order; but as it evaporates replenish with fresh water. CHAPTER V. PIGEON-LOFTS AND BANTAM-COOPS. The best place in the world for boys is out-doors, breathing good fresh air, and the best place in the world for pigeons and chickens is out-doors, breathing good fresh air. Our modern environments too often limit the amount of out-door space which boys can occupy, and also limit the supply of fresh air they can furnish their pets. In making designs for the latter we must take into consideration the limited space of a city back-yard, as well as the fact that during the extreme cold weather pigeons, chickens, and boys, all need some warm retreat where they may roost or sleep. Indeed, chickens really Need Shelter more than either boys or pigeons; the former have been known to thrive and grow lusty and strong when living like the wild animals of the forests, and every boy knows of some location where pigeons have taken up their abode with no better shelter than that afforded by an open shed, or the overhanging eaves of a house. Chickens, coming originally from tropical woods, will thrive better where their delicate combs and toes are not liable to be frost-bitten, and one is more certain not to lose his fantails, pouters, ruff-necks, tumblers, and homing pigeons, if he has a suitable loft in which to confine his pets. These considerations lead to the designing of a combined pigeon-house and bantam-coop suitable for the limited space of the diminutive city back-yards, or even appropriate for the roof of a rear extension, where there is no back-yard to the dwelling. [Illustration: FIG. 31.--Frame of Bantam-Coop and Pigeon-Loft.] By referring to Fig. 31 you will see two boys at work upon the frame of A Pigeon-Loft and Bantam-Coop which is capable of holding with comfort enough pets to gladden the heart of any healthy boy. The longest posts, A G and B H, are supposed to be about nine or ten feet high and nailed fast to the back fence. The dotted line, which cuts the frame in half, is to show that a building half the size of the one in the drawing will be plenty large enough for quite commodious quarters for the birds. After the frame has been nailed together and the protruding ends of the timbers all sawed off even with the rest of the frame, a floor must be laid to the pigeon-loft and securely nailed in place. Rough Lumber Will Answer.