MUD-CRABS 281 
apart. They are also taken by a hooked iron which is thrust into the 
hole; the crab seizes it and is then suddenly jerked from its hole. The 
adult measures about three by four and a half inches, and the body 
is from one inch to two inches thick. One of the chele is larger than 
the other, and both are proportionately enormously large, and are tipped 
with black. The terminal joints of the other four pairs of legs are 
thickly fringed with hairs and end in points which seem like nails. 
ForMER Genus Panopeus 
Eupanopeus herbstii, Eurypanopeus depressus, Neopanopeus 
texana, Rhithropanopeus harrisii (Mary J. Rathbun). These four 
species, formerly all called Panopeus, 
are small crabs which live in the mud 
and are commonly known as mud- 
crabs. They are abundant under stones 
in muddy places, and occur on the 
Atlantic coast from Massachusetts Bay 
to Florida, though they are not com- 
monly met with north of New Jersey. 
Eupanopeus herbstii is the largest one 
of the group, some of the Southern 
ones measuring two inches across. 
It is found living in mud at low-water 
mark, or burrowing in banks near 
high-tide mark. It is dark olive- 
brown, the claws broadly tipped with 
black. Eurypanopeus depressus is flat- 
tened above, and is smaller than Neo- 
. Eurypanopeus depressus, the mud-crab ; male, 
panopeus texana, which is somewhat hatiral ize. 
convex above. The last two are com- 
monly found together and have similar habits. Rhithropanopeus harrisit 
lives near high-water mark and also in salt-marshes, and is comparatively 
rare. The claws lack the dark tips of E. herbstit, and a distinct groove 
follows the edge of the carapace. 
FAMILY GRAPSIDE 
Genus Hemigrapsus 
H. nudus (Mary J. Rathbun), Heterograpsus nudus (Stimpson); H. 
oregonensis (Mary J. Rathbun), Heterograpsus oregonensis (Stimp- 
son). These two species, commonly called respectively the purple shore-crab 
and the yellow shore-crab, are the most abundant species of the California 
coast. Hundreds may be found congregated under a single rock. They 
range from Sitka to Lower California. H. oregonensis literally swarms in 
sloughs of salt or brackish water, and hundreds of uplifted threatening 
claws confront the intruder who ventures on these mud-flats when the 
tide is out. This species, the yellow shore-crab, has a nearly square 
body. Theanterior half of the side margins has two rather deep indenta- 
