190 
COMPARATIVE ZOOLOGY. 
of the hyoid 
bone ; e, tra¬ 
chea ; /, oesoph¬ 
agus ; g , epiglot¬ 
tis. 
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- 
F| g. 159.—Human man ears# There is little modulation in 
Larynx, seen in 
profile; a, half brute utterance. The Opossum purrs, the 
Sloth and Kangaroo moan, the Hog grunts 
or 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. 
