108 FRESH-WATER FISHES OF NEW JERSEY. 
examining the bottom of any ditch one can easily detect the 
Melanura lying close upon the mud as quietly as an Etheo- 
stomoid,* but if at all disturbed they immediately dart off, 
and with a rapid twirl and twist of their whole body will 
bury themselves entirely out of sight at about an angle of 
forty-five degrees, tail down. We have often tried this in a 
shallow aquarium with mud on the bottom, and always with 
the same result. The movement is too rapid to be learned 
in detail, but they always bury themselves in a hole scooped 
out with their tail, which is the most deeply buried portion 
of their body. 
A peculiarity of this fish worthy of note is the length of 
time at which it will maintain one position, especially a per- 
Fig. 30. 
7 
Smelt, Osmerus mordaz. 
pendicular one, head up and tail down. In an aquarium we 
have had them remain so four minutes, while we held just 
above the water a worm or fly. On slowly lowering these 
until they touched the water the fish would then seize them 
with a rapidity of movement equal to that of the trout. We 
have likewise seen them leap from the water a distance 
greater than their length, and seize insects that were upon 
blades of grass overhanging the ditch. The largest speci- 
men of Melanura limi ever seen by the writer measured 
seven inches. 
Frost-fish ( Osmerus mordax). We desire to record here 
*In mentioning the number of fish in this neighborhood (Trenton, N. J.) as forty- 
nine, we did not include the Etheostomoide, and the few stickle-backs that come and 
go. Both these Visión às represented in the Delaware will be studied and published 
in a separate paper 
