562 THE DESCENT OF MAN. 



ship; and some species likewise perforin what may be called in- 

 strumental music. 



In the class of Mammals, with which we are here more par- 

 ticularly concerned, the males of almost all the species use their 

 voices during the breeding-season much more than at any other 

 time ; and some are absolutely mute excepting at this season. With 

 other species both sexes, or only the females, use their voices as a 

 love-call. Considering these facts, and' that the vocal organs of 

 some quadrupeds are much more largely developed in the male 

 than in the female, either permanently or temporarily during the 

 breeding-season; and considering that in most of the lower classes 

 the sounds produced by the males, serve not only to call but to ex- 

 cite or allure the female, it is a surprising fact that we have not 

 as yet any good evidence that these organs are used by male mam- 

 mals to charm the females. The American Mycetes caraya per- 

 haps forms an exception, as does the Hylobates agilis, an ape al- 

 lied to man. This gibbon has an extremely loud but musical 

 voice. Mr. Waterhouse states.^" "It appeared to me that in as- 

 "cending and descending the scale, the intervals were always ex- 

 "actly half-tones; and I am sure that the highest note was the 

 "exact octave to the lowest. The quality of the notes is very 

 "musical; and I do not doubt that a good violinist would be ablo 

 "to give a correct idea of the gibbon's composition, excepting as 

 "regards its loudness." Mr. Waterhouse then gives the notes. 

 Professor Owen, who is a musician, confirms the foregoing state- 

 ment, and remarks, though erroneously, that this gibbon "alone 

 "of brute mammals may be said to sing." It appears to be much 

 excited after its performance. Unfortunately, its habits have 

 never been closely observed in a state of nature; but from the 

 analogy of other animals, it is probable that it uses its musical 

 powers more especially during the season of courtship. 



This gibbon is not the only species in the genus which sings, for 

 my son, Francis Darwin, attentively listened in the Zoological Gar- 

 dens to H. leuciscus whilst singing a cadence of three notes, in 

 true musical intervals and with a clear musical tone. It is a more 

 surprising fact that certain rodents utter musical sounds. Sing- 

 ing mice have often been mentioned and exhibited, biit Imposture 

 has commonly been suspected. We have, however, at last a clear 

 account by a well-known observer, the Rev. S. Lockwood, of the 

 musical powers of an American species, the Hesperomys cognatus, 

 belonging to a genus distinct from that of the English mouse. 

 This little animal was kept in confinement, and the performance 



s» Given In W. C. L. Martin's 'General Introduct. to Nat. Hist, ol 

 Mamm. Animals,' 1S41, p. 432; Owen, 'Anatomy of Vertebrates,' vol. ili. 

 p. 600. 



"■ The 'American Naturalist,' 1S71, p. 761, 



