66 The Under -Water World 



our coasts is the Sea Gherkin (Cucumaria 

 saxicola), which is greyish-white in colour, 

 with violet tentacles. It lies prone on 

 the sea-bed or, by means of its suckered 

 tube feet, perches vertically against 

 rocks, and in such situations one may 

 watch its ten tufted arms, like ten 

 grotesque hands, snatching invisible tit- 

 bits from the surrounding water, and 

 methodically placing them in the circular 

 mouth. In our largest native species 

 the Cotton Spinner (Cucumaria niger) 

 which frequents deep water, the tentacles 

 that can be completely withdrawn are 

 covered with a roll of tough skin. When 

 molested it throws out masses of white 

 threads, which swell on contact with the 

 water, and like the threads thrown out 

 by certain anemones, entangle all kinds 

 of creatures, even quite large fish, that 

 may come into contact with them. The 

 cotton spinner, like all the members of 

 the order to which it belongs, is capable 



