290 MARINE INVERTEBRATES 
color. It jumps like the latter, but not so strongly. It is found among 
the weeds and burrowing in the sand a little below high-water mark.’ 
The wet sand is often completely filled with its holes. It can be distin- 
guished byits verylong antenne. Another species, T. megalophthalma, 
is distinguished by its shorter antenne and very large eyes. Both of 
these species are grayish in color and closely resemble the sand. Found 
from Cape Cod to New Jersey. 
GENus Gammarus 
G. locusta. The animals of this genus are among the largest of the 
amphipods. The males are larger than the females, sometimes being 
one and a half inches long. They 
are abundant under stones and 
Fucus at and near low-water 
mark. Although much larger 
than the beach-fleas, they other- 
wise resemble them. They do 
not jump like the former, but 
move rapidly, lying-on the side, 
and in water swim with the back 
downward. Two pairs of the tho- Gammarus locusta, the scud. 
racic feet are chelate, and three 
pairs are longer than the others. The feet on the last segments of the 
abdomen are stiff and turn sharply back, forming a part of the tail, which 
is used most effectively in locomotion. The antennulesand antenne are 
of about the same length. Several species of Gammarus occur in the same 
range, all having the same general characteristics; some have but one 
pair of chelate feet ; the antennules are usually shorter than the antenne ; 
the females of all the species have no chelate feet. G. locusta ranges from 
New Jersey to Greenland. Thecolor is generally reddish- or olive-brown. 
G. annulatus isfound in the same places, but usually a little higher up 
on the beach; it is lighter in color, and has dark bands with red spots 
on the sides of the abdomen. G. mucronatus occurs from Cape Cod 
to Florida. Melita nitida isa smaller slate-colored amphipod found in 
some places; another is Mera levis, 
which is whitish, with black eyes. 
Genus Chelura 
C. terebrans, the boring amphipod. 
This little crustacean is associated in 
its work on submerged timber with 
the isopod Limnoria lignorum. The 
excavations of the latter are narrow 
< and cylindrical, running down into 
Chelura terebrans, the boring amphipod. the wood, while Chelura makes larger 
: : burrows in oblique lines near the sur- 
face, which give the wood the appearance of having been plowed. It 
is very active and destructive. It feeds upon the wood into which it 
burrows. Its color is semi-translucent, thickly mottled above with pink, 
