MARINE BIOLOGICAL STATION AT PORT ERIN. 



95 



inhabit mud and decaying sea-weeds, such as species of 

 Tetrastemma and Lineus, usually to be seen in our smaller 

 aquaria. We shall only illustrate here a few of the higher 

 forms of worms, which are of fair size, of active habits, 

 and are provided with feet or bristles on the segments of 

 the body. These higher bristle-bearing marine worms, 

 or " Annelids," fall into two sets — the Errantia, those that 

 wander freely, creeping over rocks and sea-weeds and 

 under stones, and the Sedentaria, those that inhabit tubes 



Fig. IX., Annelids (1 and 2 natural size, 3 magnified about 10 times). 



either fixed or moveable. Amongst the commonest of our 

 Errant Annelids are the Nereis pelagica (1) and the 

 Polynoe (Lejndonotus squamatus) (2) shown in fig. IX. 



