shape of long strings or rolls, looking at first sight like slimy necklaces.  I have seen them as much as a couple of yards long, lying loose on the grass where the frog lays them.  As soon as she has deposited them, however, the father frog hops up, twists the garlands dexterously in loose festoons round his legs and thighs, and then retires with his precious burden to some hole in the bank of his native pond, where he lurks in seclusion till the eggs develop.  Frogs do not need frequent doses of food—­their meals are often few and far between—­and during the six or eight weeks that the eggs take to mature the father probably eats very little, though he may possibly sally forth at night, unobserved, in search of provender.  At the end of that time the devoted parent, foreseeing developments, takes to the water once more, so that the tadpoles may be hatched in their proper element.  I may add that this frog is a great musician in the breeding season, but that as soon as the tadpoles are hatched out he loses his voice entirely, and does not recover his manly croak till the succeeding spring.  This is also the case with the song of many birds, the crest of the newt, the plumes of certain highly-decorated trogons and nightjars, and, roughly speaking, the decorative and attractive features of the male sex in general.  Such features are given them during the mating period as allurements for their consorts:  they disappear, for the time at least, like a ball-dress after a ball, as soon as no immediate use can any longer be made of them.

[Illustration:  POUCHED FROG.]

Some American tree-frogs, on the other hand, imitate rather the motherly Solenostoma than the fatherly instincts of the pipe-fish or the stickleback.  These pretty little creatures have a pouch like the kangaroo, but in their case (as in the kangaroo’s) it is the female who bears it.  Within this safe receptacle the eggs are placed by the male, who pushes them in with his hind feet; and they not only undergo their hatching in the pouch, but also pass through their whole tadpole development in the same place.  Owing to the care which is thus extended to the eggs and young, these advanced tree-frogs are enabled to lay only about a dozen to fifteen eggs at a time, instead of the countless hundreds often produced by many of their relations.

Tree-frogs have, of course, in most circumstances much greater difficulty in getting at water than pond-frogs; and this is especially true in certain tropical or desert districts.  Hence most of the frogs which inhabit such regions have had to find out or invent some ingenious plan for passing through the tadpole stage with a minimum of moisture.  The devices they have hit upon are very curious.  Some of them make use of the little pools collected at the bases of huge tropical leaf-stalks, like those of the banana plant; others dispense with the aid of water altogether, and glue their new-laid eggs to their own backs, where the fry pass through the tadpole