190 COMPARATIVE ZOOLOGY. 



cartilage, to which one end of the cords is attached. The 

 will cannot influence the contraction of the vocalizing 

 muscles, except in the very act of vocalization. The vo- 

 cal sounds produced by Mammals may be 

 distinguished into the ordinary voice, the 

 cry, and the song. The second is the sound 

 made by brutes. The Whale, Porpoise, Ar- 

 madillo, Ant-eater, Porcupine, and Giraffe 

 are generally silent. The Bat's voice is 

 probably the shrillest sound audible to hu- 

 i59.-Human man ears> There is little modulation in 



Larynx, seen in 



profile; a, half brute utterance. The Opossum purrs, the 



of the hyoid 01 , , Tr . TT 



bone; , tra- Sloth and Kangaroo moan, the Hog grunts 



r squeals, the Tapir whistles, the Stag bel- 

 lows, and the Elephant gives a hoarse trump- 

 et sound from its trunk and a deep groan from its throat. 

 All Sheep have a guttural voice; all the Cows low, from 

 the Bison to the Musk-ox; all the Horses and Donkeys 

 neigh; all the Cats miau, from the domestic animal to the 

 Lion ; all the Bears growl ; and all the Canine family 

 Fox, Wolf, and Dog bark and howl. The Howling- 

 monkeys and Gorillas have a large cavity, or sac, in the 

 throat for resonance, enabling them to utter a powerful 

 voice; and one of the Gibbon -apes has the remarkable 

 power of emitting a complete octave of musical notes. 

 The human voice, taking the male and female together, 

 has a range of nearly four octaves. Man's power of speech, 

 or the utterance of articulate sounds, is due to his intel- 

 lectual development rather than to any structural differ- 

 ence between him and the Apes. Song is produced by 

 the vocal cords, speech by the mouth. 



