4 THE HISTORY OF AQUARIA. 



(who was the first to keep whitebait in London, in 

 1858), and others had experienced a difficulty in 

 herring culture. In consequence of the migratory 

 habits of these fish they often injured themselves by 

 dashing against the glass or the rockwork of the 

 tank in which they were kept. As they move about 

 principally by night, it struck Mr. Kent to illuminate 

 the tank by a feeble light, so that the outlines of the 

 walls, rocks, &c., should be visible to the fish. This 

 plan succeeded admirably, and by its aid Mr. Kent 

 kept and fed whitebait until they have grown to half 

 the size of the ordinary herring. At the time he 

 made this announcement, the fish were eighteen 

 months old.* 



In addition to the above-mentioned important facts 

 with which our large aquaria have made us ac- 

 quainted, there are others not yet worked out, but 

 which are in process of careful observation. It was 

 discovered in the Hamburg Aquarium that the Phyl- 

 losoma, one of the "glass crabs," which had been 

 placed in a separate order prepared for it, is only the 

 young ol trie crawfish (Palimtru* quadricornis). The 

 Brighton Aquarium has further contributed impor- 

 tant information as to the rapidity of the growth of 

 the salmon. Before then, the growth of this fish was 

 thought to be much slower than observation and ex- 



* Mr. Kent obtained his specimens in a very young state. The only 

 person who has hatched out herrings in aquaria is Mr. Stephenson, of 

 Brixton. 



