240 SEASIDE DIVINITY. 



" jointed" is applicable to all the creatures so 

 called. As a general rule, however, the distinction 

 is sufficiently obvious. But in their internal 

 structure the articulata differ widely from all the 

 members of the group to which reference has 

 already been made. Their nervous system is not, 

 as in the radiaries, placed in the centre, from 

 which it extends in rays or branches, but it con- 

 sists of a brain from which a thread of the nervous 

 matter extends along the body, having at certain 

 distances along the thread nervous centres, called 

 ganglions or knots, from which proceed the nerves 

 which supply the limbs or other extremities. The 

 articulata "are arranged in five different classes, 

 each comprehending animals distinguished by some 

 general character. 



The first of these classes to which we shall sup- 

 pose our attention to be directed is that of the 

 Annellata. The animals comprised in this class 

 are very numerous, and various specimens may be 

 discovered with a little industry on almost every 

 sandy sea-shore at low water. The whole class 

 may be considered as represented by the common 

 leech or the earth-worm, the bodies of which 

 creatures are formed of numerous rings, a circum- 

 stance which gives origin to the generic term, de- 

 rived from the Latin word annellus, signifying a 

 little ring. 



A very common, but, when carefully examined, 

 a very interesting example of the animals of this 

 class is the lug, a large worm inhabiting the 

 sand and much employed as a bait by fishermen. 



