1 6 THE HAUNTS OF LIFE 



OF UNCERTAIN POSITION. There are many 

 seashore animals whose relationships are 

 obscure. Thus there are the Polyzoa, to which 

 the common Sea- Mat (Flustra) belongs the 

 animal on which Darwin wrote his first scientific 

 paper. The Polyzoa form a large class, with 

 a great variety of representatives, some sea- 

 weed-like (Flustra), till you look into them ; 

 some coral-like (Cellepora) ; some gelatinous 

 (Alcyonidium)] some like zoophytes (Gemel- 

 aria), but ever so much higher in structure. 



ECHINODERMS. The prickly skinned animals 

 are represented by star-fishes, brittle-stars, sea- 

 urchins, and sea-cucumbers, forming a well- 

 marked " kenspeckle " class, with a great 

 tendency to become very calcareous, least so in 

 the sea-cucumbers, most in such sea-urchins as 

 the sand-dollar. It is a most interesting sight 

 to watch the common star-fish creep up the 

 vertical surface of a submerged rock by means 

 of its remarkable hydraulic locomotor system, 

 while the sea-urchin, when moving on a flat sur- 

 face, hobbles along on the tips of its five teeth ! 



STINGING ANIMALS. Sea-anemones nestle 

 like flowers in the niches of the rocks. In 



