146 KOCK-POOLS. 



It would extend this chapter too much to mention, 

 or even to glance at, the other groups of animals, ex- 

 amples of which are to be found on the rocky sea-shore. 

 Enough has been said to show the richness of the 

 subject. No shore is so absolutely barren but it will 

 provide some interesting object for investigation among 

 the lower animals, and there will generally be found 

 everywhere examples of all the greater groups. And 

 there are few shores which produce nothing but com- 

 mon kinds ; the most unfavourable-looking places often 

 unexpectedly yield something which is rarely found. 

 The pursuit of Marine Zoology is, therefore, always 

 interesting, for the attention is kept constantly alive. 

 With the varying nature of the ground the population 

 varies. And nothing can well exceed the beauty of 

 a clear rock-pool, seen under strong sunlight, and 

 through a calm surface, tenanted by its varied ani- 

 mated tribes, all fulfilling the duties allotted to their 

 several kinds. The transparent shrimp, now resting on 

 its oars, midway in the water, watching your motions 

 with its peering eyes, and attentive to the slightest 

 disturbance, now darting through the pool, and hiding 

 himself among sea-weeds ; the basking Sea Anemone 

 displaying his starry flowers; the Purple Rock Urchin* 

 studding the bottom of the pool with spiny globes ; 

 and the quiet Molluscs leisurely pursuing their way, 



* This species, Echinus lividus, is peculiar to the west coast of 

 Ireland, where it is very common, living in society in pools between 

 tide-marks. Its habits are as curious as its aspect is beautiful. It 

 is chiefly remarkable for burrowing circular holes in limestone, clay- 

 slate, or even in trap-rocks. 



