94 CRUSTACEA. 



Corophium, Lat. 



C. longicornis; Cancer grossipes, L.; Gammarus longicornis, 

 Fab. j Oniscus volutator, Pall., Spic. Zool., Fascic. IX, iv, 9; 

 Desmar., Consid., XLVI, 1, called Pernys, on the coast of Ro- 

 chelle, lives in holes, which it forms in the mud, that is covered 

 with hurdles, called bouchots, by the inhabitants- The animal 

 does not make its appearance till the beginning of May. It wages 

 everlasting war against the Nereides, Amphinoma?, Arenicolse, 

 and other marine Annelides, which inhabit the same locality. A 

 curious spectacle is presented by these Crustacea, when the tide 

 is coming in; myriads of them may then be seen moving in every 

 direction, beating the mud with their great arms, and diluting 

 it in order to discover their prey is it one of the above men- 

 tioned Annelides they have discovered, which is ten or twenty 

 times larger than themselves? they unite to attack and devour 

 it. The carnage never ceases until the mud has been thorough- 

 ly turned up and its inequalities levelled. They do not even 

 spare Molluscae, Fishes, or dead bodies on the shore. They 

 mount upon the hurdles which contain Muscles, and fishermen 

 assert that they will cut the threads that keep them there, in 

 order to precipitate them into the mud, where they may devour 

 them at their leisure. They appear to breed during the whole 

 summer, as females carrying their ova are to be met with at 

 various periods. Waders and different Fishes prey upon them. 

 For these interesting observations we are indebted to M. D'Or- 

 bigny, Senior, conservator of the Rochelle Museum and cor- 

 responding member of that of Paris(l). 

 The second section Heteropa, Lat. is composed of those with 

 fourteen feet, the last four of which, at least, are unarmed and des- 

 tined for natation only. It comprises two subgenera(2). 



Pterygocera, Latr. 



The thorax divided into several segments; four antennas furnished 

 with setae or hairs in bunches; all the feet natatory and the last large 



(1) See Encyclop. Method., article Podocere. 



(2) This and the following 1 section, in the first edition of the Regne Animal, 

 form the second of the Isopoda, that of the Phytibranckiata. But independently of 

 our having 1 discovered mandibular palpi in some of these Crustacea, the form of 

 the subcaudal appendages appears to us to approximate them much nearer to the 

 Amphipoda, than to the Isopoda. We may also observe that these animals, of 

 which we have seen but very few, have not yet been well studied. 



