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When the waters rise, they approach the shore, and seize 
on marine animals, incapable of resisting, or which have 
perished. They are very voracious, and assemble in great 
numbers on the carcases on which they feed. It is prin- 
cipally during the night that they proceed to plunder. Ne- 
vertheless, as they do not always regain the sea with suf- 
ficient promptness, and they cannot swim, they are often 
exposed to be stranded in the low waters. If they do not 
find, in their neighbourhood, some hole to take refuge in, they 
contract their feet, squat down in some corner, and await in 
tranquillity the return of the tide, to arrive at the open sea. 
It is the individuals thus detained, that are most frequently 
collected by fishermen ; for these Crustacea will but seldom 
take the bait, and are not easily caught in nets. Around the 
islands of America and India, where the bottom of the sea, 
near the coasts, is visible in calm weather, they are harpooned 
with a long pole to which a fork is attached. In other places 
they are taken by divers. 
The Portuni, called also etrilles by M. Cuvier, scarcely 
differ from certain crabs, and particularly from the carcins of 
Dr. Leach. 
According to the report of M. Bose, the portunus which 
lie regards as the species named pelagians, by Fabricius, 
swims almost continually, with facility, and even with a sort 
of grace. It can sustain itself upon the water, and for a con- 
siderable space of time, without giving itself any apparent 
motion. It has no other points of repose, excepting the 
varecs, and other plants of the Atlantic ocean, where it is 
found in great numbers; it lives on other marine animals. 
Another portunus, the haslala of M. Bose, and which he has 
observed on the coasts of Carolina, also swims extremely 
well ; but it walks as much as it swims. In general, it 
parades slowly, on the edge of the sea, or at the mouth of 
rivers, when the tide is flowing, for the purpose of seeking its 
