THE MICROSCOPE. 



Jan. 



groups of hooked bristles resembling figure 3 ; these are 

 the little points that projected from the sides of the body 

 and are arranged so that the hooks point backwards 

 thus keeping the animal from slipping. In the common 

 earth-worm of our gardens these bristles or setsB are ar- 

 ranged with four groups to a segment and two bristles 



in each group. There are two ventral groups and one on 

 either side of the body (figure 1). Sometimes there are 

 nine groups of seise and there may be several bristles in 

 each group. Sometimes they extend over the dorsal as 

 well as the ventral side of the body. Sometimes they 

 are arranged in regular rows as in figure 5, or they may 



