No aquarium can be considered complete without a frog or a tadpole. Watching a tadpole develop into a frog is a favorite amusement with young naturalists. First of all they gradually increase in size, and when this process has been carried to a certain extent the hind legs develop, and we have a curious compound - half fish, half reptile. After a time the fore legs make their appearance, the tail drops off, and the animal changes entirely its habits and necessities. It no longer lives in the water, for it is now an air-breathing creature; and whereas it formerly subsisted on vegetables and dead animal matter, it now feeds chiefly upon living insects, which it captures with wonderful dexterity. It is a singular fact, however, that these changes are greatly influenced by the condition in which the tadpole is placed. If confined in a dark place the change never comes at all, and it remains a tadpole all its life.
Besides the frog there are several other reptiles which are worthy of a place in the tank. The most interesting of these are the newts. There are several species, all quite pretty, and adding much to the variety of the stock. Some persons, it is true, can not endure the sight of these creatures; and where such idiosyncracies exist, the newts must be omitted. It must be borne in mind that where frogs and newts are kept some provision must be made for allowing them to spend a large portion of their time out of the water, otherwise they will certainly be drowned.