ADAPTATION FOR PROTECTION FROM ENEMIES 97 



1. Examine a specimen of Volvox. Why may this be 

 considered a colonial protozoan and not a many-celled ani- 

 mal ? What is gained by the colonial habit ? 



2. Is the colonial habit common or rare in sponges and 

 coelenterates ? What is chiefly gained ? 



3. Describe the community life in one of the insects in 

 each of the following groups : — 



a. ant, honeybee, termite. 



b. bumblebee, paper wasp, hornet. ' 



c. mining bee. 



d. carpenter bee, mud wasp, digger wasp. 



4. Name the host or hosts in the following cases : 

 trichina, liver fluke, malarial parasite, tapeworm, hook 

 worm. Give the life history of one or more of the para- 

 sites just enumerated. What is the effect of parasitism 

 on the structure of the parasite .' 



5. What is the relation between ants and plant lice .■' 

 Show how this relation is mutually helpful. Mention other 

 cases of symbiosis that you have come across. 



6. With what animal are barnacles often associated .' 

 What is the habit of the pea or oyster crab ? What are 

 " guest bees " } What structure is lacking that is found in 

 other bees } What are often found in the cavities of 

 sponges ? Why are these associations called commensal- 

 ism rather than symbiosis } 



Summary. 



1. Into what groups can animal associations be divided 

 based upon the number of species concerned ? 



2. From the standpoint of protection, is this a good or a 

 bad method of protection .' 



3. What disadvantages can you see in this method of 

 protection. 



