i84 POPULAR SCIENCE MONTHLY. 



tHe same time being the species that furnishes the legs so much 

 enjoyed by many epicures. When Huxley gave his biological 

 chapter on these animals, he used the Anglo-continental types, R. 

 temporaria and R. esculenta, the latter form being the one used 

 for the table in Europe. One of the most interesting species that 

 have been described is the one discovered by Mr. Wallace in Bor- 

 neo a number of years ago. It has been popularly called the " fly- 

 ing frog," from the fact that it has toes of great length, and these 

 are fully webbed to the tips. If the animal wishes to descend 

 from the top of a high tree it has only to make the leap, and by 

 spreading out its toes it converts its feet into four veritable para- 

 chutes, and thus this little aerial batrachian reaches terra firina 

 in safety. Among the most curious types are the tree frogs ; and 

 Gibson says these "are readily distinguished from all others by 

 having the ends of their toes dilated into knobs or disks, gener- 

 ally provided with a sticky secretion, by means of which they can 

 cling to the leaves and branches of trees. They are small, elegant, 

 and exceedingly active creatures, the males possessing loud voices, 

 of which they make copious use during the breeding season and 

 on the approach of rain." Frogs have from remote times been 

 regarded as weather prophets, and at the present day, in some 

 parts of Germany, the European tree frog (Hyla arhorea) is used 

 as a barometer. A few of them are placed in a tall bottle pro- 

 vided with miniature ladders, the steps of which they ascend dur- 

 ing iine weather, seeking the bottom again on the approach of 

 rain. 



Anatomical structures of a variety of kinds are characteristic 

 of different species of frogs, having to do with the voice organs. 

 So it is that many croak, some chirp, and some almost bellow. 

 Many emit noises most disagreeable to all ears, while others give 

 vent to sounds that under some circumstances are quite enjoy- 

 able. Darwin says, " Near Rio de Janeiro I used often to sit in 

 the evening to listen to a number of little Hylce- [tree frogs], 

 which, perched on blades of grass close to the water, sent forth 

 sweet, chirping notes in harmony." This, however, is not the case 

 with another species that occurs in Surinam, also a tree frog, en- 

 dowed with an extremely disagreeable voice, and, what is worse, 

 they congregate together in great numbers, and then, when they 

 unite in their piping, they have been known to drown the orches- 

 tra of the Paramaribo theater. 



Frogs live principally upon insects, and these they capture 

 with their peculiarly formed tongue. This organ is soft and 

 extensible, being at the same time covered with a viscid secretion. 

 Anteriorly it is closely attached to the floor of the mouth, while 

 behind it is to a large degree free. The free part is thrust for- 

 ward when the frog desires to capture an insect, and the latter 



