36 THE SEAS 



(Plate 15), are also inhabitants of rocky shores. They are 

 covered with spines — which in allied animals from warmer 

 seas may be of great length and, sometimes, thickness — 

 and must be handled carefully. 



Some shore fishes can always be found under stones. 

 The most common is probably the butterfish [Centronotus 

 gunellus), about six inches long, eel-like, flattened from sida 

 to side and with nine or more dark spots edged with yello\^ 

 down the middle of the back. The smooth blenny [Blennius 

 pholis) (Plate 8), can withstand long periods out of water 

 and is common on the shore, as are the bullhead or father- 

 lasher {Coitus hubalis), with its large head armed with 

 four formidable spines, the five-bearded rockling {Motella 

 miistela) to be recognized by the five barbels under its 

 snout, and various kinds of sucker-fish {Lep ado g aster), 

 whose hinder (pelvic) fins are united to form a sucker by 

 means of which the fish fastens itself to rocks. 



In holes and cracks in rock live worms of various kinds, 

 also a quaint crustacean called Gnathia and the little sea 

 gherkins {Cucumaria), which can frequently only be removed 

 by splitting the rock with a crowbar. Here, too, are rock- 

 boring bivalves, especially the common Saxicava, though 

 the large " Piddock " (Pholas) and some of its smallef 

 allies are common in some parts. 



There is no more fascinating or more beautiful spot on 

 the shore than a typical rock pool. Its sides and bottom 

 are usually covered with a many-coloured carpet of weeds, 

 sponges, hydroids, sea mats and sea squirts, amongst which, 

 like flowers, glow the rich colours of anemones (Plate 16). 

 The commonest of these — by no means confined to the pools 

 but common on the higher parts of shore — is the beadlet 

 (Actinia), usually a deep red or brown, but sometimes red 

 with green spots (the strawberry variety) or, less frequently, 

 a bright green. At the base of the tentacles is a row of blue 



