252 THE ZOOLOGIST. 



the changes in the fish-fauna on these grounds. The movements 

 of the Herring are independent of such phenomena, and we now 

 know that the Herring abounds all the year round, and can be 

 captured — irrespective of currents and temperatures — in con- 

 siderable numbers at any time. Moreover, hydrographical 

 influences are powerless to cause it to deviate in its progress to 

 the coast to spawn. The sudden disappearance of the Herring 

 from its wonted spawning grounds is not due to hydrographic 

 influences, any more than to the guns of the artillery volunteers, 

 as the fishermen supposed. Dr. H. M. Kyle, a trained marine 

 zoologist, plainly says that neither the temperature-charts nor 

 those for salinity exhibit a true parallelism with the biological 

 phenomena, and suggests weekly instead of monthly data. 

 Some, however, may be of opinion that even hourly records 

 would be equally futile. It would almost seem to be as reason- 

 able to explain the passage of the larvae of animals dwelling on 

 the bottom to the surface of the sea by similar data. 



It is well known that in a shallow bay a cold frosty morning 

 is bad for fishing, that extreme cold kills fishes and their eggs, 

 and that the high temperature of summer favours swarms of 

 fish-food, which, however, equally abounds in the arctic seas. 

 Fishes, moreover, are not so sensitive to changes of temperature, 

 to changes in salinity, or to other phenomena, as supposed ; 

 neither (ta they dread currents. The Salmon, the Sturgeon, 

 and the Eel are at home both in the sea and fresh water, and 

 the Flounder, the Mullet, the Sea-Perch, the Sprat, and the 

 Sparling take little notice of varying salinities. The Baltic 

 Herring can readily be acclimatized to fresh water, even to the 

 extent of being killed, if by accident it suddenly falls into sea- 

 water. The Shanny from the rock-pools is indifferent to immer- 

 sion in fresh water. Even the transparent floating eggs of the 

 Flounder may be heated in a test-tube till they rush up and 

 down with the currents, and yet may be safely hatched subse- 

 quently. Further, irrespective of temperature and currents, the 

 very young fishes invariably follow the laws which regulate their 

 appearance at particular seasons. Thus the young God, Green- 

 Cod, Haddock, and Whiting, after their earliest (larval) stage, 

 are oblivious of currents in their movements — on the one hand 

 to shallow, and on the other, to deep water, and the same may 



