476 
BULLETIN OF THE BUREAU OF FISHERIES 
FOOD AND FEEDING HABITS 
It has been shown in that section of this paper dealing with the distribution of 
the young of the summer flounders, that the fry like the larger young and the adults 
live on the bottom. Since they habitually dwell on the bottom it follows that they 
must acquire their food there. No study of the stomach contents of small fish has 
been made during the present investigation. A considerable number of large flounders 
has been examined, however, and their food consisted almost wholly of fish, supple- 
mented sparingly by crustaceans. Hildebrand and Schroeder (1928, p. 166) report 
fish as the principal food, supplemented by squids, shrimp, crabs, and Mysis for speci- 
mens from Chesapeake Bay. 
Flounders frequently are seen in shallow water, partly covered with sand or 
mud, and in color they resemble the background. That is to say, if the fish happen 
to be on sand of a fight color, for example, the body is light in color and generally 
profusely speckled and spotted, thereby more closely resembling the sand. How- 
ever, if the background consists of dark mud the fish are dark and quite uniform in 
color. In other words, these flounders are able to simulate to a remarkable degree 
the color and pattern of the bottom. (See Mast, 1916, pp. 177-238, pis. XIX- 
XXXII.) Thus concealed from easy vision, they lie in wait for their prey. Although 
generally rather sluggish fish, they are able to dart from their partial concealment 
with remarkable rapidity to seize their prey, and they strike with great force. These 
feeding habits of the summer flounders are easily observed by confining the fish in 
aquarium tanks, for the fish live well and feed readily in captivity. The senior 
author once kept about a dozen flounders for nearly two years in a tank supplied with 
a small stream of running water for the purpose of watching their behavior. The fish 
lost all fear of a person in several months time and would strike at a man’s finger 
when inserted in the tank just as readily as at a minnow. A laborer who was cleaning 
the tank, for example, suffered a painful injury one day when a fish struck his hand at 
a moment when he was offguard. 
It is of interest to note that this lot of fish, held in confinement for a long time, 
when finally liberated apparently had lost the sense of self-preservation. The fish 
were placed in the water on a sandy beach at high tide but failed to follow the water 
with the receding tide, remaining on the beach where they had settled upon liberation. 
When it became evident that they would remain there to die, they were placed in 
deeper water. It is not known, however, whether these animals again learned to cope 
with nature and shift for themselves or whether they perished. While color and pat- 
tern simulation of the bottom and partial concealment in sand and mud no doubt at 
times serve the fish as protection from enemies, it very probably is far more impor- 
tant as a concealment from its prey until the critical moment comes when it is time 
to strike. 
SYMPHURUS PLAGHJSA (Linneeus). Tonguefish; sole 
The tonguefish is known from Chesapeake Bay southward to Florida, occurring 
on both coasts of the Florida peninsula. It is common to numerous at Beaufort, 
N. C., but rare farther northward. Hildebrand and Schroeder (1928, p. 178) say, 
“It is a rare fish in Chesapeake Bay and unknown to most of the fishermen.” It 
seldom attains a length of 7% inches, and the usual length of adults is only 4 or 5 
inches. It has no direct commercial value and appears to enter into the food of com- 
mercial fish only occasionally. Therefore, its economic value appears to be very 
slight. 
