AMPHIPODA; SAND-HOPPER, &c. 259 



is a very characteristic example of this Order. It is extremely- 

 abundant on our shores ; and may often be seen in vast numbers 

 on the sands, especially when the sun is shining upon them and 

 the tide is retreating. The whole surface of the sand, or rather 

 the air for a few inches above it, appears as if alive with them ; 

 for they are incessantly leaping to an elevation, which is, for their 

 minute size, very considerable, as if they were in the height of 

 enjoyment. They burrow in the sand ; and seldom enter the 

 water. Their food probably consists of the minuter animals, and 

 of the decomposing animal and vegetable remains, which are 

 left in the sand by the sea. The Gammarus pulex (Fig. 589), 

 which is nearly allied to the preceding in structure and in 

 its leaping powers, is an inhabitant of fresh water brooks; 

 being especially abundant in those, in which there is an accu- 

 mulation of decaying vegetable matter. The Corypkmm is 



remarkable for its very long 

 antennae, and for its pre- 

 daceous habits. It is very 

 abundant on the coast of 

 La Rochelle, where it forms 

 extensive burrows in the 



Fio. 590. COR YpnruM LONOICOKNR ; a, terminal , 1 , . ., 



segment of the tail. sand, only making its ap- 



pearance, however, at the 



beginning of May. It keeps up a continual war with the Anne- 

 lida, which inhabit the same neighbourhood ; and also attacks 

 Mollusca and even Fishes, as well as dead animal matter. 

 Scarcely anything is more curious, than to observe these creatures 

 at the rising of the tide assembled in myriads, moving about in 

 all directions, beating the mud with their arm-like antennae, and 

 mixing it with water in order to discover their prey. If they 

 meet with Annelids even ten or twenty times their size, they 

 unite together to attack and devour them ; and the carnage does 

 not cease, until the whole of the mud has been turned over and 

 examined. It is said that they sever the byssus, by which the 

 Mussels are fixed ( 1030) ; so as to cause them to fall, and thus 

 to enable them to be more readily attacked. They are in their 

 turn devoured by Fishes and by many Shore-Birds. The Crustacea 



