ON CRUSTACEA. 317 



dead bodies cast on shore by the waves ; they are themselves 

 also the prey of several fishes and aquatic birds ; they also 

 form an excellent bait for taking small fishes by the line- 

 Like the other Crustacea, they change skin in summer, ail 

 operation which they execute very promptly. " The males," 

 says M. Bosc, carry their females, which are smaller than 

 themselves, between their feet, and this burthen does not 

 hinder them from leaping." According to M. Risso, the 

 females lay several times in the year, a fact, which, however, 

 appears to need further confirmation. They carry their eggs 

 under the scales of the breast, and when the young are dis- 

 closed, they remain there until they are strong enough to seek 

 their food themselves. 



In the subgenus CoROPHltM, a very curious species is 

 the longicoriie. This is called pernys on the coasts of La 

 Rochelie : it lives in holes which it forms in the mud. The 

 animal does not begin to appear until the commencement of 

 May. It carries on a continual war against the nereids, the 

 amphinomee, the arenicolae, and other marine annelid.es, which 

 make their dwelling in the same places. There is nothing 

 more curious than to see, at the rising of the tide, myriads of 

 these Crustacea agitating themselves in all directions, striking 

 the mud with their long arms, and thinning it for the purpose 

 of discovering their prey. When they find one of these anne- 

 lides, often ten or twenty times larger than themselves, they 

 unite for the purpose of attacking and devouring it. They do 

 not give over their carnage until they have smoothed and 

 thoroughly searched all the mud and slime. The muscle 

 fishers even pretend that they cut the threads which retain 

 these shell-fish, so as to make them fall into the mud, and 

 then that they devour them. They appear to multiply during 

 the whole of the fine season, since females are found at dif- 

 ferent times charged with eggs. The gralla) and many fishes 

 devour them in their turn. 



