THE PRESENT. 



mals being in turn preyed upon by other races, aquatic, 

 aerial, and terrestrial, and creating extensive calcareous 

 masses with their shelly coverings the niollusca fulfil im- 



Molluscan Aspect of Animal Lite. 



portant vital as well as physical functions. From the 

 enduring nature of their testaceous coverings, they become 

 import ant indices to the palaeontologist, and the interpreta- 

 tions of geology have largely profited by the persistency of 

 their remains. Next in order come the Articulata the 

 worms, insects, spiders, and crabs known at once by their 

 many-ringed, segmented, or jointed bodies. Inhabitants of 



