172 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [466] 
ters are always planted, thus greatly modifying the natural conditions 
of such localities and introducing a large number of species not prop- 
erly belonging to the true muddy bottoms. 
The shores of the muddy estuaries and ponds, or lagoons, are usually 
low, flat, and bordered by more or less extensive salt-marshes, with the 
surface generally just above high-water mark of ordinary tides, but lia- 
ble to inundation by unusually high tides. These marshes are always 
traversed by winding and sluggish tidal streams of brackish water and 
by smaller ditches, and the surface is often diversified by small pools or 
ponds of impure brackish water, in which there is generally a deep de- 
posit of soft, slimy mud and decaying organic matter, which often be- 
comes putrid, and exhales fetid gases. All such waters, whether in the 
ditches or pools, and however filthy they may be, are inhabited by cer- 
tain kinds of invertebrate animals, and they are also frequented by mul- 
titudes of minnows and other small fishes, which undoubtedly find 
abundant food in such places. 
In these brackish pools and ditches we find certain beetles, both in the 
adult and larval stages. Among these the most conspicuous is Hydro- 
philus quadristriatus HORN., a large, black species, which appears to be 
common. The larva of the salt-marsh musquito (Culex, sp.,) also lives in 
such situations, and the adults in August, September, and October, so 
swarm in these marshes as to render it extremely unpleasant to go on 
or near them. The larve of an Hphydra also occurs, and many other 
insects will doubtless be found in these places when carefully sought for. 
One Amphipod, the Gammarus mucronatus, commonly lives in the most 
brackish pools and among the grass on the marshes. The prawn, Pale- 
monetes vulgaris, (Plate L, fig. 9,) is also very abundant in these pools 
and ditches, even where the water is but little salt, and also occurs in 
immense numbers on the muddy bottoms and among the eel-grass of the 
estuaries. In the pools there are also myriads of small Entomostraca 
of many kinds, upon which the prawn and other species feed, while the 
Entomostraca find an abundance of ciliated Infusoria and other micro- 
scopic animals for food. ; 
We find several species of crabs burrowing in muddy banks along the 
shores of the estuaries, as well as along banks of the streams and ditches 
in the salt-marshes. The most abundant of these is the marsh fiddler- 
crab, Gelasimus pugnax, which is often so abundant that the banks are 
completely honey-combed and undermined by them. These holes are of 
various sizes up to about three-quarters of an inch in diameter, and de- 
scend more or less perpendicularly, often to the depth of two feet or 
more. Occasionally in summer these crabs will leave their holes and 
scatter over the surface of the marshes, which at such times seem to be 
perfectly alive with them, but when disturbed they will scamper away 
in every direction and speedily retreat to their holes, but occasionally, 
at least, they do not find their own, for sometimes the rightful owner 
will be seen forcibly ejecting several intruders. It is probable that at 
