Ixxx 



That this peculiar organization is connected with the vo- 

 cal powers of this bird, 1 conceive there can be very little 

 question ; it is with surprise I have read the remark of Meckel, 

 that this bird has no voice. Those who have frequently 

 visited these birds in the Zoological Gardens, must have no- 

 ticed the different sounds they emit ; in fact, they have two 

 distinct voices, just as they possess distinct organs ; the most 

 ordinary is a harsh, disagreeable, hissing voice, not unlike that 

 of the common goose ; this is frequently heard, as the bird 

 follows visitors round the enclosure in expectation of food ; 

 this voice I attribute to th,e structure, or organization of the 

 superior glottis. The other, and more peculiar sound, is only 

 occasionally emitted, probably because, while in a state of 

 captivity, the ordinary excitements are not so frequently pre- 

 sent; this resembles a low, hollow sound, not unlike that 

 caused by gently striking a large drum, or moving an empty 

 barrel ; sometimes it is sharp, short, and sudden ; at other 

 times it is long and muffled, like the rolling of thunder, or of 

 a smoothly-running distant carriage ; sometimes it is soft, 

 continued, and rather melodious ; but at others it is disagre- 

 ably interrupted by harsh and rough grunting sounds. The 

 animal only occasionally emits this voice ; on visiting the 

 Gardens, in hope of hearing it, I have been frequently disap- 

 pointed ; on other occasions, the birds have repeated it several 

 times. The care-taker informs me that in his morning visits 

 to open the aviary and feed the birds, they frequently make 

 this extraordinary noise, and which he compares to the sound 

 of thunder. The ear detects this sound as proceeding from 

 the upper part of the sternum, that is, from the position of the 

 sac, and, while making it, the animal extends and alters the 

 curve of the neck, and fills this tracheal bag ; there can be no 

 doubt, therefore, that this voice is connected, in part, with 

 the inferior glottis, or the two narrow bronchial openings, and, 

 in part, if not essentially, with this peculiar appendix ; there 

 is nothing in the superior larynx, or in the inferior, alone, that 



