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EXPLANATORY INDEX. 



ones till they merge into a prolonged roar, which dies gradu- 

 ally away with a mournful cadence. 



"When not more than one or two hundred yards away, 

 and consequently plainly heard, they commence with a series 

 of short howls, which break off into grunts, and, at every 

 repetition, become longer and longer till their voices have got 

 fairly in tune, when they give their final roar, which dies as 

 gradually away. Then, after an instant's silence, a few deep 

 grunts are given, as if the remains of the compressed air in 

 their throat drums were being got rid of. Listening carefully 



to the performance, one can detect a voice at a much higher 

 key than the others, especially in the dying-away portion. 

 The Indians say this is made by a dwarf monkey of the same 

 family which accompanies every troop. I was of the opinion 

 that it was the voice of a female Howler, but the Indians, 

 who are very careful observers, said it was not. With their 

 black negro-like faces, and long red beards covering the bony 

 howling apparatus below their throats, they are curious- 

 looking creatures." 



Some specimens of the Red Howler which were brought to 



