Chap. XII. 



AMPHIBIANS. 



27 



These animals, however, offer one interestini^ sexual 

 difference, namely in the musical powers possessed by 

 the males ; but to speak of music, when applied to the 

 discordant and overwhelming sounds emitted by male 

 bull-frogs and some other species, seems, according to 

 our taste, a singularly inappropriate expression. Never- 

 theless certain frogs sing in a decidedly pleasing man- 

 ner. Near Eio de Janeiro I used often to sit in the 

 evening to listen to a number of little Hylse, which, 



Fig. 32. Megalophrys montana. The two left-hand figures, the male ; the two 



right-liand figures, the female. 



perched on blades of grass close to the water, sent 

 forth sweet chirping notes in harmony. The various 

 sounds are emitted chiefly by the males during the 

 breeding-season, as in the case of the croaking of our 

 common fro^-.^^ In accordance with this fact the vocal 

 organs of the males are more highly developed than 

 those of the females. In some genera the males alone 



^- Bell, ' History of British Eeptiles,' 1849, p. 93 



