Thilo’s memoir on »Die Umbildungen an den Gliedmaßen der Fische«. 189 
had hitherto been supposed. In my opinion at least, this organ 
cannot have this function in all the fishes, in which it does exist. 
And consequently it is evident that I can still less acknowledge an 
author to be right who had urged that the air-bladder can only be 
a sound-produeing organ (quite apart from the fact that it must be 
considered as established that it has an other funetion besides). But 
it is just as clear that it is quite unpardonable in me if I have 
concealed such statements in the literature. Thus, in fact the state- 
ment of Dr. TuıLo quoted above implies a serious charge against 
me, even if he has not meant it so. 
I therefore take the liberty to ask Dr. THILO to quote some — 
or but one — of the »frequent« passages in the literature, where 
he must have read a statement like that which he quotes in in- 
verted commas, since he can say that it is »only too frequently« 
to be met with. 
