176 THE SEA SHORE 



with soft, flattened, unsegrnented bodies, though some of the larger 

 species are really wormlike in form, and are more or less distinctly 

 divided into a chain of segments. Many of them are marine, and 

 may be seen gliding over stones left uncovered by the receding tide 

 with a smooth slug-like motion, and when disturbed in a rock pool, 

 occasionally swimming with a similar smooth motion by the aid of 

 their cilia. They avoid bright light, and are consequently generally 

 found on the under surfaces of stones, especially in rather muddy 

 situations, and where the stones are covered with a slimy deposit 

 of low forms of life. In these turbellarians the mouth is situated 

 on the tinder surface, thus enabling the animal to obtain its nourish- 

 ment from the slimy surface over which it moves, and it is also pro- 

 vided with an extensile proboscis that aids it in the collection of its 

 food. The digestive tube is generally very complex in form, extend- 

 ing its branches into every part of the soft body ; and, there being 

 no special organs of respiration, the animal derives all the oxygen 

 required by direct absorption from the water through the soft 

 integument. 



When searching for turbellarians on the sea shore one must be 

 prepared to meet with interesting examples of protective colouring 

 that will render a close examination of rocks and stones absolutely 

 necessary. Some of these worms are of a dull greyish or brownish 

 colour, so closely resembling that of the surface over which they 

 glide that they are not easily distinguished ; and the thin bodies of 

 others are so transparent that the colour of the stone beneath is 

 visible through them, thus preventing them from being clearly 

 observed. 



Overturned stones should be examined for their flattened bodies 

 gliding along rapidly in close contact with the surface. They may 

 be removed without injury by placing a wet frond of a sea weed 

 close to the stone, in front of one end of the body, and then urging 

 them to glide on to it by gently touching the opposite end. Some- 

 times, however, the turbellarians remain perfectly still when exposed 

 to the light, in which case they are even more difficult to detect, 

 but a little practice will soon enable one to distinguish them with 

 readiness. 



Allied to the turbellarians are the Spoon Worms or Squirt Worms, 

 some species of which inhabit deep water round our shores, where 

 they burrow into the sand or mud of the bed of the sea. These 

 form the class Gephyrea, and consist of creatures with sac-like or 

 cylindrical and elongated bodies, and a protrusible proboscis, which 



