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, an 
operation which they execute very promptly. “ The males,” 
says M. Bose, carry their females, which arc 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 Corophium, a very curious species is 
the longicorne . This is called pernys on the coasts of La 
Rochelle : 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 
amphinom®, the arenicolae, and other marine annelides, 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 gralke and many fishes 
devour them in their turn. 
