MUD-LOVING FISHES. 387 
carefully searched for a trait characteristic of this fish as 
compared with Æ. obesus, and have uniformly failed to do so. 
The habits of the species are those of the Centrarchid:e gen- 
erally, modified in so far as being merely more of a mud- 
loving species. So purely a mud-dwelling fish are they 
that we have frequently found them in water so shallow, that 
they marked the mud with their pectoral fins in swimming ; 
preferring such shallow water, with the mud, to that which 
was deeper, to which they had access, because it was over a 
stony bed. In winter they congregate in deep water, and 
unless care is taken to dig well into the mud they will not 
be taken in the ordinary scoop-net. We found, during the 
past winter, in one instance, that a large number had appar- 
ently scooped out a basin in the bottom of a little pond. At 
any rate, closely huddled together, in a small space, some- 
what deeper than the surrounding bed of the pond, was a 
large number. Examination of several showed they were 
then taking no food. The stomach of each specimen, and 
the whole digestive tract, in fact, were empty. 
The main interest attaching to this species, at least to us, 
is the fact of its occupying many small, sluggish streams, 
similar and side by side with others that harbor, though less 
abundantly, the ZE.'obesus. We never yet have found them 
associated in small streams, in the tributaries of the river; 
yet, in the Delaware itself the Æ. obesus is occasionally, and 
the guttatus frequently found. North-east of Trenton, in the 
Spar-kill, a creek emptying into the Hudson, and in the 
streams along the coast, emptying into the bays, the Æ. 
obesus abounds ; and the guttatus has not been found. Along 
the Delaware both are found, the guttatus more abundantly. 
Professor Cope has found Z. guttatus near Richmond, Vir- 
ginia, and (verbal communication) has not found it about 
Philadelphia. It is undoubtedly in the Delaware, at Trenton 
—distanee thirty-seven miles. We have been thus particu- 
lar in stating its habitat, because the fact of its not associ- 
ating with the E. obesus is a mystery we cannot explain, 
