The Drum 315 
were deeper, a roaring boom so penetrating that 
it could be heard throughout a large room. It 
happened that I was looking at one of the fishes 
when the sound was made, and noticed a very 
slight opening of the mouth and gills, a convulsive 
movement. The drumming is possibly a sexual 
call, at least it is heard more in the spring when 
the fishes are breeding, both sexes uttering it; 
that produced by the male is the loudest, that of 
the female is said to be the most musical. The 
drumming sound is produced by the air-bladder, 
and whether it can be heard to any great distance 
beneath the water is a question unsolved. I have 
been fortunate in hearing the vocal accomplish- 
ments of a number of fishes, and several are 
certainly as interesting as the drum’s and one as 
startling. The common grunt (Hemulon) of the 
Florida reef would always grunt and groan ina 
most despairing way when caught. The loudest 
noise I have heard made by a fish was uttered by 
a midshipman, a fish nearly a foot long, which I 
kept in a tank at Santa Catalina Island. This 
fish would utter a loud resonant croak or bark 
under water which could be heard with startling 
distinctness fifty feet away. 
Nearly all of the Scizenidz are sound utterers, 
