THE EUROPEAN SEAS. 



23 



drawn from the salt waters beneath, became con- 

 vulsed and paralysed in their involuntary ascent 

 through the fresh waters above. They were more 

 dead than alive when we placed them in basins, and 

 none the livelier for having a new supply of water 

 given them taken from the surface of the sea. Yet 

 whilst these truly marine creatures were living and 

 thriving below, numerous forms of entomostraca, 

 incapable of enduring the briny fluids of the depths, 

 might be sporting in the lighter and purer element 

 above. This phenomenon, which I have often ob- 

 served since, suggests the possibility of a mode of 

 destruction of fishes which would aid in explaining 

 the peculiar aspect not unfrequently presented by 

 the fossil remains of those animals. In many places 

 where petrifactions of fishes are found, their bodies 

 are observed to be more or less contorted and con- 

 vulsed. Many marine fishes when suddenly plunged 

 into fresh water — and this is the case also with 

 numbers of marine invertebrata — die rapidly, almost 

 instantaneously, in convulsions, their bodies becoming 

 suddenly stiffened, their fins spread and beautifully 

 displayed. I have availed myself of this method of 

 piscicide when desirous of obtaining sea-fishes in 

 the state best adapted for delineation. Now it is not 

 improbable that fishes of strictly marine habits, and 

 incapable of enduring sudden immersion in fresh, or 

 nearly fresh water, when too eagerly pursuing their 

 prey, or too timidly flying from their pursuers in 

 localities such as those I have referred to, might 



