5 2 Dwellers of the Sea and Shore 



having no rays. Moreover, all are characterized by 

 the great development of movable spines. They are 

 sometimes called ocean hedgehogs, on account of their 

 spiny covering. More sluggish than the starfishes, 

 they seldom wander far from their accustomed haunts. 

 Various species of these animals are found from high- 

 tide mark to very great depths. 



Sea cucumbers are creatures whose general appear- 

 ance is wholly unlike the starfish and the sea urchin. 

 But there are certain characteristics (of too technical 

 a nature to be detailed here) they have in common with 

 those animals which places them undoubtedly in the 

 same company. They may roughly be described as 

 sausage-shaped with a rosette of tentacles at one end. 

 They are inhabitants of every variety of bottom; but 

 the majority are found in the sand and mud which, like 

 the earthworm, they eat for the organic particles there- 

 in contained. 



Most feather stars and crinoids live only in deep 

 water and are seldom found near the shore. The cri- 

 noids are generally known as sea lilies because of their 

 general form. They have a long, jointed stalk, one end 

 of which is attached, while the other bears the disk and 

 featherlike arms of the animal. The sea lilies remain 

 permanently fixed where they grow, but the feather 

 stars, which at one stage of their life are stalked, de- 

 tach themselves from this part of the body and swim 

 about by means of their arms. 



Thus I have given in the briefest form possible the 

 general characteristics of the five classes of animals 

 which make up the phylum Echinodermata. The com- 

 plete life histories of by far the greater part of this 



