276 SUPPLEMENT 



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 PoETUNi, called also etrilles by M. Cuvier, scarcely 

 difler from certain crabs, and particularly from the carclns of 

 Dr. Leach. 



According to Ihe report of M. Bosc, the portunus which 

 he regards as the species named jjelagicus^ 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 luistaia of M. Bosc, 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 

 l^arades slowly, on the edge of the sea, or at the mouth of 

 rivers, when the tide is flowing, for the purpose of seeking its 



