Page:Popular Science Monthly Volume 59.djvu/84

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74
THE POPULAR SCIENCE MONTHLY.

ricans. Having taken the eggs, however this may be done, the frog emits a clear musical sound and goes hunting its own food, thinking, we may suppose, as little of its offspring as do our own common toads and frogs. The young require a long time to bring them to the hatching stage, and have also an unusually large and peculiar gill on each side.

The tree-frogs of the tropics furnish examples of egg-carrying habit as well as of nest-building. Thus in Ceylon a tree-frog (Rhacophorus reticulatus) carries its eggs in a cake-shaped cluster of about twenty firmly fixed to its belly, as indicated in Fig. 6. This time it is not the male, but the female, that aids the coming race by giving it transportation and protection. Probably, however, it is the male and not the female of a frog of the Seychell Islands (Anthroleptes Seychellensis) that carries about its young on its back. This is a most complex case, for the eggs are laid upon moist earth or rotten logs and kept moist by the body of the frog until they hatch; they have large tails.

PSM V59 D084 Seychelles and the dutch guianese frogs with their young.png
Fig. 7. Fig. 8. 

and even the beginning of hind legs. Then the youngsters get up on the back of their parent and stick there till their development is complete. The peculiar little tadpoles have great power of adhesion, and can stick to the sides of a glass dish as they do to their parent's back (Fig. 7). Another such case occurs in Trinidad and in Venezuela. When the ponds dry up the young tadpoles of the frog Phyllohates trinitates, which are as yet without legs, though they have tails, stick themselves firmly to the back of the male frog (whether it is their father or the father of some other tadpoles does not appear), and in this way are carried 'pick-a-back' to some larger pond. Similar habits have been observed in the frogs Dendrobates trivittatus and Dendrohates braccatus.

Again, a frog (Hylodes liniatus) of Dutch Guiana is found with its tadpoles attached to its back, as seen in Fig. 8. The young, from a dozen to twenty, are attached, as shown, with their heads turned towards the middle of the mother's back and do not fall off, even when she leaps rapidly away. Thus the mother, and not the