SKELETOK AND LARYNX OF XENOPIJS AND PIPA. 75 



the muscles can be effected, — a sound similar to, though probably 

 more rapidly repeated than, the taps given by certain wood- 

 boring beetles. 



Haying arrived at this conclusion, it was most gratifying to me 

 to hear Mr. Arthur Thompson, when recounting at a recent 

 meeting of the Zoological Society his observations on the habits 

 of the Surinam toads then breeding in tbe Society's menagerie, 

 mention, quite incidentally, the rapping noise whicli they made. 

 All those anatomists who have paid any attention to the subject 

 have remarked on the failure of anyone to hear the sound, which 

 they were convinced must emanate from such a complicated 

 laryngeal apparatus. Grronberg, in his recent contribution, says 

 (18. p. 637) " es wiirde von grossem Interesse sein, zu erfahren, 

 ob Pipa wirklich eine diesem Apparat entsprechende Stimme 

 hat. Mein Freund, Freiherr A. von Klinckowstrom, der lebende 

 Wabenkroten in Surinam oftmals beobachtet hat, will nieraals 

 einen Laut von ihnen gehort haben." And even in the current 

 year Wilder writes (42. p. 291) that the matter " is deserving of 

 careful investigation from the side of the physicist, as well as 

 that of the naturalist." Mr. Thompson's remarks were there- 

 fore most opportune. 



On further inquiry I gathered that the sounds were heard by 

 many visitors to the Society's Grardens, who variously described 

 them as resembling the tapping of a key on the glass of the tank 

 in which the animals lived, the striking of two chisels together, 

 and the distant sound of a bricklayer's trowei. All were agreed 

 that there is a metallic ring about the sound, and that two, three, 

 or four taps follow one another in quick succession, — then, after 

 a pause there comes a repetition, and so on throughout the day 

 and night. There is at present insufficient evidence that the 

 noise is an accompaniment of the amatory overtures, but it is 

 worthy of remark that these animals were mute before the 

 breeding period, and have since relapsed into silence. Mr. 

 Thompson stated it as his firm belief that both sexes shared in 

 the clamour and that their voices were indistinguishable; but, 

 personally, I fail to see how such a tapping sound could possibly 

 emanate from the female larynx, where there is no backward 

 growth, enlargement nor ossification of the arytenoids. 



At this same meeting of the Zoological Society Mr. G. A. 

 Boulenger, F.B.S., stated that the Xenopus during the breeding 

 period utters a sound which he compared with that produced by 



