NA TURAL SCA VENGERS. 1 5 1 



devouring decaying vegetation. The common peri- 

 winkle (Littorina littorea) is another good scavenger, 



Fig ill. 



Ormer (Haliotis tubcrailata}. 



Fig. 112. 



Limpet (Patella vutgaris). 



but a voracious feeder. The limpet (Patella vitl- 

 garis) doei its work more slowly, but effectively, and 



