SHALLOW-WATER FAUNA. 



27 



Many other examples to illustrate this feature 

 of the Sea-weed Fauna could be quoted, but 

 sufficient has been said at present if we have 

 indicated to the reader the manner in which, by 

 the indirect influence of light, the form and 

 colour of animals may be modified for their life 

 among the marine plants. The presence of light, 

 however, modifies directly the character of the 

 animals themselves in many respects. 



The statement that many of the animals of 

 the shallow water are provided with eyes because 

 there is light is, when carefully examined, found 



ABC D 



FIG. 5. Diagrams of Eyes of A Whelk, B Lobster, C Scallop, D Fish. 



to be strictly true, however anomalous it may 

 seem to be. There must have been light in the 

 shallow waters of the sea when the first pri- 

 mordial forms of life made their appearance, and 

 it was this light which, step by s'tep, led to the 

 evolution of the most complicated and perfect 

 forms of eye from the simplest pigment spot of 

 the Protozoan to the eye of the Lobster and the 

 Fish. We may say that all animals that freely 

 swim in the shallow waters or that crawl and 

 creep on the rocks and sands at the bottom are 

 provided with eyes. The Fish are provided with 

 a pair of eyes which present us with the same 



