426 SMITHSONIAN MISCELLANEOUS COLLECTIONS [voL. 48 
tion of the opercular valve closes the branchial aperture, thus forcing 
the water out at its upper angle, as from a kind of vent. This is 
also the place where the water is ejected when the fish is swimming 
free in the midst of that element. 
The fish remained all night in the same position in which I had 
left it the day before. . . . On the following day I had it taken 
out, and touching its belly I found the stomach to be empty; I 
therefore supposed the fish to be very hungry. Having a few live 
specimens of Gobius niger I placed them near the Uranoscopus 
which had again buried itself in the sand. The Gobius passed over 
the head of the fish and stayed there, but the Uranoscopus would 
not take hold of one, either because it was so much annoyed, or 
because such fishes were not is natural prey. 
It may be concluded from what has been said that the Urano- 
scopus is adapted for a life hidden in the sand or mud. I do not 
doubt that this habit is designed to procure its food for it. If it 
were a means of defence, the offensive weapons with which nature 
has provided the fish and which are of the most redoubtable kind 
would be almost superfluous. As the fish does not appear from its 
original organization to be a very agile swimmer, and especially 
from the weight of its head, those weapons will assist it when 
moving about in the water, either to change its place or to approach 
the female. The shape of its mouth will not permit it to lay hold 
of its prey in any other way than the insidious one which was 
already spoken of. I am assured by the fishermen that this fish is 
never taken with a line, but with a spear or sometimes in a net. 
As a matter of fact, it is nearly always seen in the market injured. 
The young of this species hunt smaller fishes according to the capac- 
ity of the stomach; and these latter fishes again pursue very 
small creatures, and thus there is an agreement between the instinct 
of the prey and that of the enemy. 
In the stomach of a Uranoscopus more fishes are generally found ; 
this shows that when it has obtained some prey, it continues its 
insidious manceuver, until its belly is filled. The abdominal cavity 
has an enormous gall-bladder, while in other fishes which feed 
exclusively on fish, that organ is of ordinary size. But in Urano- 
Scopus a greater quantity of bile may be needed, ,because the fish 
is very voracious, and probably also because the flesh of the sardines, 
which are most frequently found in its stomach, is fatty. 
It might be asked whether the various dispositions which render 
the fish adapted for staying buried in the ground, were established 
from the beginning, or whether they are the effect of adaptation. 
