Crustacea. 6683 



assistant in the pursuit of Natural History. The water is not so 

 clear, the animals are not so happy and natural, as the same water 

 and the same animals in their original position. Few are the animals 

 that will not pine in prison ; and those that do not, soon put on 

 appearances that are unknown in the free state. But still, with all 

 the drawbacks, the vivarium is invaluable to naturalists ; and it is 

 only in them that the habits of the frequenters of the ocean can be 

 studied as living animals. The shrimp and the crab, out of the viva- 

 rium, and their congeners, are but known to many when boiled red 

 or dressed in a salad ; and those that may have been seen alive were 

 in a frighted condition, as they ran from the cover of one stone upon 

 the beach to that of another, or struggling to escape from the fisher- 

 man's trap. But, thanks to Mr. Warington and Mr. Gosse, the 

 awkward, hopping prawn, that was always jumping it knew not 

 where, and falling it knew not how, and so difficult to hold, is found 

 to be among the most graceful animals that float through the element 

 in which it lives. Under the posterior portion of the body, long, 

 sweeping, plume-like, feathery legs (pleopoda) beat the waters more 

 gracefully than fish's tins, as the proud beauty traverses the ocean 

 many fathoms deep. 



In a paper published in the ( Annals of Natural History' Mr. 

 Warington tells us that he has observed the hungry prawn watching 

 for its food ; and when it has been given to him, a piece will occa- 

 sionally fall to the bottom without being perceived by the animal, 

 which might perhaps have been more attracted by some other object 

 at the moment. But the long, sweeping antennae (the posterior pair) 

 are always on the watch ; they slowly beat the waters in every 

 direction ; and Mr. Warington says that the moment one of them 

 cuts the column of water through which the piece of food had fallen 

 to the bottom, the animal becomes cognizant of the fact, and turns 

 and hunts it up, or chase it through the water as Mr. Warington drew 

 it forwards on a piece of stick. My friend Dr. Dansey has recently 

 assured me that in his vivarium all the smaller fish fall a prey to the 

 prawns, who hunt and chase, giving them no rest until they capture 

 them. The instructed scent of the harrier and foxhound is pointed 

 out as a wonderful possession ; and so it is ; but is it less wonderful 

 or less true that the prawn can chase its prey at the bottom of the 

 sea ? What has been proved with respect to the imprisoned animal 

 in the confined water of the vivarium, is more than probably 

 increased in force in the free creatures of the sea. In shallow 

 estuaries whole shoals of different species darken the stream in their 



