ECHIXODERMATA. 7 



nevertheless, their relationship to the Urchins and Sta 

 fishes is manifestly shown, by their apparatus of locom 

 tive suckers, which are of precisely the same structure i 

 those of the Echinus. As if, however, also to manife 

 an affinity with the Polype forms, there still exists in tl 

 Holothuria a circle of branched tentacles, which surrour 



Fro. 50. HOLOTHURIA:. 



the mouth. These are capable of being withdrawn im 

 the body, but are commonly protruded in expectation < 

 prey, which is seized and dragged to the mouth by thei 

 appendages. They greatly resemble in appearance tl 

 tentacles of some of the Acfinia\ especially when tl 

 Holothuria has buried its whole body in the mud or sam 

 with the exception of these branched tentacles, whic 

 expand like the petals of a flower. A species named 



The Cotton-Spinner (HoloUwria Xigra\ sometimes called tl 

 "Nigger," is very common in deep water, off the coast of Cornwal 

 it is held by the fishermen in great detestation, on account of i 

 Biimy appearance, and from an idea that where the "Niggers" a 

 numerous, and get into the Crab-pots, neither crabs nor lobsters a 

 caught. These animals are frequently near a foot in length, ai 

 thick in proportion. They sometimes draw themselves up into 

 kind of ball and if touched or disturbed, throw out a bunch 

 white taper thivads of givat tenacity, that stick to everything th( 

 touch, and no doubt constitute a means of defence. 



The Siphon-worms (SipuHculu*)* (Fig. 51) have alengtl 

 ened and slender body, and all the aspect of worms, wit 



* Sipunculus, from an^ov, a tube. 



