CHAPTEE II. 



THE STUDY OF SHORE ANIMALS. 



Where to begin How to begin The study of common animals 

 Characters of limpets Their structure and habits The common 

 crabs and their characters Classification of shore animals 

 General hints as to methods. 



WE have in the preceding chapter considered in outline 

 the special nature of the surroundings among which 

 shore animals pass their lives, and the nature of the adapta- 

 tions by which they respond to the peculiarities of these 

 surroundings. In this chapter we have to consider how the 

 would-be naturalist is to become acquainted with the teem- 

 ing life of the seashore. The first question to be asked is, 

 Where shall we begin 1 ? It is obvious from the foregoing 

 that except where the luxury of a dredge is available the 

 field of action must be the tidal rocks. It is true that the 

 mud-flats at the mouths of rivers and streams may furnish 

 many different worms, some burrowing sea-urchins and sea- 

 anemones, cockles, mussels, and razor-shells; and the streams 

 themselves may abound with shrimps, sand-hoppers, sand- 

 eels, shore crabs, and other hardy creatures; yet, alike for 

 accessibility and for wealth of types, the rock pools claim 

 pre-eminence, and it is with them that it is advisable to 

 begin. 



It is probable that the question, Which rocks 1 will often 

 be determined by other causes than the naturalist's predi- 

 lections, but it is nevertheless worth while to point out what 

 conditions are especially favourable. For my own part I 

 should be inclined to regard as the most important requisite 

 that of ready accessibility. Where pools of considerable 

 depth are within easy reach of the shore, the observer may 



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