JULY. 131 



creeping along the pools, so conspicuous in their movements 

 and colouring as to suggest that they do not need protec- 

 tion. Probably they have a taste which is objectionable to 

 the large marine carnivora, and are desirous to proclaim 

 their identity, so that fishes and other mollusc - eating 

 animals may make no mistake about them. On the other 

 hand, the edible molluscs, like oysters and mussels, are 

 furnished with a good thick shell by way of protection. 

 The little fishes of the rock-pools are usually parti-coloured, 

 like the amphipoda black, grey, and white. They dart 

 hither and thither with rapidity, and when resting on the 

 bottom or among the weed are almost indistinguishable 

 from their surroundings. Even the pretty sea-anemones 

 are coloured in exquisite harmony with the rocky beds in 

 which they hide ; but here it is not protection they seek, 

 but something very different. How deep-seated in Nature 

 lies the principle of deception ! These innocent-looking 

 lumps of jelly, whose whole inside is a digestive cavity, 

 spread out their petal-like tentacles in a radiating ring, 

 ready to grasp and engulf any unwary animal which comes 

 within their reach. Having no means of progression, and 

 consequently of aggression, they must resort to deception 

 to catch their prey. So they assume a flower-like appear- 

 ance, and when fully opened are remarkably beautiful 

 organisms. The thing which strikes one most when con- 

 sidering these facts is how certain forces in Nature have 

 worked through countless generations of organisms, modi- 

 fying their structure in whatever direction will bring them 

 into and keep them in accord with their surroundings, so 

 that we are almost compelled to speak of these organisms 

 as if they were themselves conscious agents in this work of 

 evolution. 



If we turn over some of these stones near the rock-pools 

 we shall almost certainly disturb a colony of crabs. Here 

 are large purple-spotted ones* like the stones they hide 

 among, and there are olive-green or brownish species more 

 like the seaweeds in hue. They hide while the tide is low, 



* Hcttrograpsus sexden/atits. 



