The common frog . Fig. 13.—RhitiofiJiry71US dorsalis. Almost all frogs and toads pass the first stages•of their existence in water, going through a ivQ^, III.] THE COMMON FROG. 33 tadpole stage, and all are more or less aquatic whenadult. The only exceptions are Pipa, Nototrema,Opisthodelphys, and the Hylodes before referred many kinds, however, are, when adult, inhabi-. ilG. 14.—Skeleton of the Flying Dragon.(Showing the elongated ribs which support the flitting organ.) tants of trees. The question may suggest itself tosome, Are there any which can be said in anysense to be aerial ani
The common frog . Fig. 13.—RhitiofiJiry71US dorsalis. Almost all frogs and toads pass the first stages•of their existence in water, going through a ivQ^, III.] THE COMMON FROG. 33 tadpole stage, and all are more or less aquatic whenadult. The only exceptions are Pipa, Nototrema,Opisthodelphys, and the Hylodes before referred many kinds, however, are, when adult, inhabi-. ilG. 14.—Skeleton of the Flying Dragon.(Showing the elongated ribs which support the flitting organ.) tants of trees. The question may suggest itself tosome, Are there any which can be said in anysense to be aerial animals .^ Birds are almost all D 34 THE COMMON FROG. [chap. capable of true flight, as also are those aerial existingbeasts the Bats, and as were those extinct reptilesthe Pterodactyles. Certain squirrels and opossumscan take flitting jumps by means of an extensionof the skin of the flank, and a similar, though muchgreater extension, supported by elongated freelyending ribs, is found in the little lizards {Draco)called Flying Dragons. The class of Fishes supplies us, also, with an ex-ample of aerial locomotion in the well-known Flying Fish. Since, then, every other class of vertebrate animals(Beasts, Birds, Reptiles and Fishes) presents us withmore or fewer examples of the aerial species, wemight perhaps expect that the Frog class would alsoexhibit some forms fitted for
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlondo, bookyear1874
