HOLOTHURIOIDEA. 



443 



leathery envelope, capable of great dilation and contrac- 

 tion, and generally containing more or less of calcareous 



FIG. 670. 



Holothurian, or " Sea-Cucumber," Pe.ntacta frondosa, North Atlantic. 



FIG. 671. 



Plates from the skin of Holothuriaiis, magnified. 



particles. The different species vary from an inch to a 

 foot in length. 



Pentacta frondosa (Fig. 670) is very abundant at Grand 

 Menan, on the coast of Maine. It resembles the kind 

 called Trepang, which the Chinese use for food. 



