ARCHITECTURAL EFFORT 9] 
An earlier observer, Bosc, who studied this same 
species in Carolina, declares that these crabs were to be 
seen in thousands and even in millions on the margin of 
the sea or of tidal rivers. He remarks that, if a man or 
any animal comes among them, they lift up the large claw, 
and holding it forward, as if challenging their opponent to 
fight, in that attitude they scurry off sideways. They 
have, he says, a great number of enemies among the otters, 
bears, birds, turtles, alligators, and the like, but they are 
so prolific that the devastation made among them by these 
foes is imperceptible. He occasionally saw the ‘calling 
crabs’ swarming over a carcase on the shore and disputing 
with the vultures for strips of the carrion. He was very 
anxious to see them make their burrows, but they never 
would work in his presence, doubtless not trom shyness, 
but from some prudential motive.  Gelusimus mina, 
Leconte, the largest of the American ‘ fiddler-crabs,’ lives 
in salt marshes or fresh water. Over the mouth of its 
burrow Mr. T. M. Prudden ascertained that this crab often 
constructs a regular ovenlike arch of mud, and that it sits 
in this doorway on the look out for whatever may befall. 
Professor Smith kept a large male of this species in a 
glass jar containing nothing but a little siliceous sand, 
moistened with pure fresh water, for over six months. It was 
for ever pacing round the jar and trying to climb out, was 
never observed to rest or show fatigue, ‘and after months 
of confinement and starvation was just as pugnacious as 
ever.’ 
The species Gelasimus arcuatus, de Haan, already 
mentioned, was observed by Krauss in South Africa as 
occupying muddy ground, and having a bluish-grey colour 
suitable to its residence. The appropriateness of the 
generic name will be appreciated in the light of his in- 
cidental remark that ‘it is truly comical to see these crabs 
with uplifted arms in countless numbers scampering over 
the dark mud.’ 
Gonoplaw (originally spelt Goneplat and Goneplaz), 
Leach, 1814, is a North-Atlantic and Huropean genus, 
which till lately contained only one species, Gonoplaa 
