36 



is one of the parasitic forms living in man. The 

 lamprey eel lias a round mouth armed with teeth like 

 a diamond drill, with which it bores its way into 

 the bodies of other fish and lives on their flesh. 



The remora illustrates commensalism^ that is, the 

 association of animals of different kinds 5 in which the 

 two live in harmony and often to their mutual advan- 

 tage. The remora attaches itself to a shark by the 

 disk on its head and is carried about for weeks, only 

 leaving its host to make sudden dashes off for food. 



