124 



ANIMAL COLOEATION. 



says Prof. Agassiz, " with a set of eyes enabling it to see both 

 laterally and downward,— it has also an immense pair facing 

 dbrsally, so that the animal has a free field of vision in all 

 directions." The eyes of many Zoefe (the larvte of decapod 

 crustaceans), as well as of many young fishes, are entirely out 

 of proportion, so large are they, to the eyes of the adult. If 

 we are to assume that eyes are meant to see with (which is. 

 however, by no means clear, in our sense of seeing, in some of 



rig. S. — Fhivnima seiknUtrio. 



the lower forms) these pelagic creatures must be endowed 

 with unusual clearness of perception. If this be so, are they 

 deceived by the transparency of the animals upon which they 

 prey ? The great marauders of the pelagic fauna are, accord- 

 ing to Prof. Agassiz, the copepod crustaceans and Jlysis 

 (fig. 9), both well off' in the matter of eyes, the latter especially.. 

 A large part of the pelagic fauna is formed by fishes in various 

 stages of development, from the egg to the adult j and these, 

 although pellucid and invisible to our eyes, unless a minute 



