S YMBIOSIS. 



337 



occurs between plants and animals. Various species of plants 

 attach themselves to ani- 

 mals by which they are 

 carried about. The plant 

 is thus aided in obtaining 

 the materials for food, 

 and not infrequently the 

 plant conceals the animal 

 from another which seeks 

 it as prey. In this way 

 certain crabs are hidden 

 by algne attached to them. 

 One of the most striking 

 cases of protective m imicry 

 is that in which an Aus- 

 tralian fish has acquired 

 surface outgrowths which 

 imitate almost precisely the 

 appearance of brown sea- 

 weeds, so that, when quiet, Fig. 376.— a young cl 



. , , ,., cles, t, on the roc 



it looks like a stone to Uoff. 



which seaweeds had attached themselves. Thus it often 



escapes its enemies, as does the crab with its 



mask of real seaweeds. 



B. Helotism. 

 462. 1. Fungi and algae. — Helotism 

 exists between fungi and algae, constituting 



F Hd?S; "Ealnil the bodies known as lichens, in which the 

 '• fungus is the master and the alga the slave. 

 (See ^[ 54</, and fig. 377.) The same 

 fungus may be found enslaving more than 

 one species of algae even within the same mycelium. The 

 prOtonema of mosses or even the leaves of some small 



enveloping an alga, 

 us. Mag- 

 nified 950 diam. — 

 After Kemer. 



