828 MANUAL OF NATURAL HISTOEY. 



Grecian Archipelago, another species (E. lividus) 

 is also occasionally eaten by goatherds and fisher- 

 men. 



In the following arrangement the orders are those 

 of Professor E. Forbes ; the families are from vari- 

 ous sources, those of the Cirrhigrada being in ac- 

 cordance with Dr. Gray's monograph. 



I. CLASS,— ECHXNODERMS (Echinodermata). 



Animal mostly free ; body in the typical orders 

 radiate, with a quinary division of segments, in the 

 rest molluscoid or annuloid ; usually covered with 

 a coriaceous skin, strengthened in some by calca- 

 reous plates or spines. Progression by means of 

 cirrhi or suckers, or, in some, by contraction and 

 extension of the body. 



I. OKDEB. — Worm-like Echinoderms (Vermigrada). 



Body annuloid ; cirrhi obsolete, or only as bristles ; 



motion effected by contraction and extension of the 



body ; mouth seldom surrounded with tentacles. 



1. Family. — Spoon-Worms (Thalassemidse). Body 

 oval or oblong ; proboscis with a long, fleshy 

 appendage ; vent at posterior extremity ; 

 tentacles none. 

 • 2. Family. — Fork-nosed Worms (Bonnelliidse). Body 

 oval ; proboscis very protractile, forked at 

 the extremity ; vent at posterior extremity ; 

 tentacles none. 



3. Family. — Tailed - Worms (Priapulidae). Body 



