364 ANIMAL BIOLOGY 



is colored like a dried leaf, the upper side being bright 

 colored and conspicuous. 



Contrasted with the protective coloration of many 

 forms, are the bright colors of certain animals which are 

 poisonous or have a disagreeable taste. Such animals 

 are said to possess a warning coloration. Examples are 

 afforded by the conspicuous spotted Salamandra macu- 

 losa of Europe, whose skin produces a copious supply of a 

 virulent poison. Many poisonous snakes are very con- 

 spicuously colored and the same is true of many stinging 

 insects. It has been found that certain non-poisonous 

 forms closely resemble species having a warning colora- 

 tion. This resemblance is called mimicry k (see p. 23) 

 and is commonly explained as having been developed 

 because resemblance to a protected form is an advantage 

 in deceiving enemies. A great many species of butter- 

 flies show a remarkably close resemblance to other species 

 which are known to possess a disagreeable taste and odor. 



A very common kind of adaptation is shown by the 

 organisms called parasites. These creatures usually are 

 carried by others from which they obtain their sustenance. 

 We have already become acquainted with many parasitic 

 species from various groups of the animal kingdom. In 

 the Protozoa we have parasitic Amoebae, parasitic infusoria 

 and flagellates and the entire group of Sporozoa. Among 

 the flat worms the trematodes and the cestodes, or tape- 

 worms, are entirely parasitic. There are numerous 

 parasitic round worms, or nematodes. There are large 

 groups of parasitic forms among the Crustacea, such as 

 the fish lice, whale lice and parasitic barnacles. The 

 arachnids have their parasitic ticks and mites, and the 

 insect world contains thousands of species parasitic on 

 plants and animals. 



Parasitism forms a relatively easy way of getting 



