THE STORY OF ANIMAL LIFE 



son to a small Gherkin ; pre- 

 sumably one that has been very 

 badly pickled for the colour 

 of the animal is brownish and 

 by no means green. The mouth 

 of a Sea-Cucumber is surround- 

 ed by a circlet of tentacles (par- 

 tially indicated in the diagram, 

 Fig- 38). The body is elongated 

 and crawls along: the "star" 

 shape, so characteristic of the 

 Echinoderms, is scarcely to be 

 recognised except in cross sec- 

 tion, where the longitudinal 

 rows of tube-feet are seen to 

 outline a pentagon. The skele- 

 ton of the Sea-Cucumber is of 

 a very meagre description. In- 

 stead of forming a rounded 

 case, as in the Sea-Urchin, it 

 consists only of loose pieces of 

 very small size, situated below 

 the skin. The Starfishes are 

 intermediate in this respect. 

 Their " skeleton " consists of 

 . vast number of pieces or 

 "ossicles," which are of fair 

 size, but are not closely 

 united, as in the Sea-Urchin. 

 They are, however, so nu- 

 merous and so well knit, 

 that the skeleton of a 

 dead Starfish presents 

 the complete outward 

 form of the animal. It 



FIG. 38. 

 A Sea-Cucumber, Cucumaria 



. 

 must be noted that the 



