FIDDLER-CRABS 283 
of fiddler-crabs occur on the Atlantic coast. They congregate in 
immense numbers, and excavate their holes in convenient localities 
above the reach of the tides — on salt-marshes, far up the estuaries, and 
along the mouths of rivers, even where the water is quite fresh. The 
males have one claw very largely developed; the other chela is small. 
The former is likened to a fiddle, the latter to a bow, and this, toge- 
ther with the waving motion of the large claw, gives them their popular 
name. This comparatively enormous claw is a distinguishing feature by 
which they are easily recognized without other description. The female 
has claws of small and equal size. These crabs burrow holes in the 
mud or sand half 
an inch to two 
inches in diameter 
and a foot or more 
in , depth. The 
upper part is nearly 
perpendicular, be- 
coming horizontal 
below, with a cham- 
ber atthe end. One 
species, U. iminaz, 
constructs an arch- 
way over the mouth j 
of its burrow, in Uca (Gelasimus) pugilator, the fiddler-crab; male. 
which it sits and 
surveys the surroundings, but quickly retreats when danger approaches. 
The crab makes its burrow by scraping up the mud or sand and forming it 
into pellets, which it carries under the three anterior walking-feet on the 
under side, using the legs on the side moving forward, and the fourth 
one on the other side, to climb out of the hole. After peering cautiously 
about, the crab emerges, and carries its load four or five feet away 
before dropping it; then again looks about before quickly running 
back; and, finally, turning its stalked eyes, looks in all directions and 
suddenly disappears, soon to return with another load. The burrows 
cover considerable areas, and the crabs are so abundant that the marshes 
and shores sometimes seem to be alive with them. When alarmed, they 
lift the large claw and run sideways, after the manner of all crabs, to 
their holes, and, as many are likely to retreat into the most convenient 
one, the owner often finds his burrow occupied by other tenants, whom 
he unceremoniously proceeds to pull out. U. minax ranges from southern 
New England to Florida, and lives on salt-marshes farther away from 
the sea than the others, and often where the water is quite fresh. It is 
larger than the other species, and can be distinguished by ared patch at 
the joints of the legs. It is a vegetarian in diet, living on small alge. 
This is the species which constructs a little observation-house over the 
mouth of its burrow. It can live out of water, and without food, for several 
days. JU. pugilator lives on sandy and muddy flats and beaches near 
high-water mark, where the sand is compact and somewhat sheltered, 
and ranges from Cape Cod to Florida. This species, like U. minaa, is a 
vegetarian. U. pugnax is exceedingly abundant on muddy banks and 
ditches of salt-marshes, the banks being sometimes completely honey- 
combed and undermined by them. It ranges from Cape Cod to Florida. 
