TRANSACTIONS OF TIJK SECTIONS. ^7 



ZOOLOGY AND BOTANY. 



An Account of the Organ of Voice in the New Holland Ostrich. By 

 James Macartney, M.D., F.R.S., S(C. 



Those who have visited zoological gardens containing the os- 

 triches of New Holland, must have remarked the very singular 

 sound produced by these animals ; it is a species of grunt, but much 

 softer than that of the hog, and involving the vibration of so large a 

 volume of air, that the persons standing near the bird may feel a 

 tremor communicated to their own bodies. Having had an oppor- 

 tunity of examining the structure of the animal. Dr. Macartney 

 found that there exists a mechanism amply sufficient for the pro- 

 duction of the extraordinary sound above mentioned. In the middle 

 of the trachea there is a large opening, directly communicating with a 

 membranous cell of very considerable extent, which is placed 

 under the skin of the neck. There is no peculiarity of structure at 

 the bifurcation of the air tube into the two bronchi, and this part is 

 only furnished with the two long muscles usually found in the organ 

 of voice in birds when it possesses the simplest mechanism ; conse- 

 quently the peculiar sound belonging to the New Holland ostrich is 

 entirely occasioned by the reverberation or resonance produced in 

 the membranous bag connected with the front of the trachea. 



Several birds of the duck and merganser genera are known to 

 have the voice modified, and the volume of tone increased by dilata- 

 tions or convolutions of the trachea. It is by a convolution of 

 this kind that the land rail also is enabled to utter the creaking 

 sound for which this bird is so remarkable. The neighing of the 

 horse and the hideous cry of the ass are effected by the addition of 

 some membranous chambers situated near the exit of the air from 

 the wind-pipe. In some monkeys there is a membranous bag commu- 

 nicating with the top of the trachea, and the howling baboon has cham- 

 bers composed of bone conjoined with the larynx. The bull-frog, which 

 is heard to so great a distance, is provided with reverberating pouches ; 

 but Dr. Macartney is not aware of any example in the class of birds, 

 except the New Holland ostrich, where the organ of voice is furnished 

 with a membranous bag for augmenting the sound, nor any instances 

 amongst the other classes of animals in "which pouches are connected 

 with the middle part of the trachea. The structure- of the organ for 

 producing sound in the New Holland ostrich is therefore considered 

 to be peculiar to that bird. 



As the animal from whence these observations were made was a male, 

 the author was inclined to suppose that the peculiarity of voice did not 

 belong to the female, which is usual in birds ; but he has since ascer- 

 tained that it belongs |o both sexes, which is a still further deviation 

 from common rule. 



VOL. v.— 1836. 



