INVERTEBRATES. CORALS 31 



bleached yellowish color commonly seen to deep brown <>r black, or 

 yellow and red, in varying shades. 



In Alcove 3 arc shown coral animals and their relatives: plantlike 

 hydroids which often are mistaken for sea moss, hut which really are a 

 scries of polyps living in a colony; jelly fishes with their umbrella- 

 Alcove 3 shaped bodies and long, streaming tentacles; brilliantly 



Polyps colored sea anemones, sea fans and sea plumes; the 



magenta colored organ-pipe coral, the stony corals, and the precious 

 coral of commerce, ('oral polyps, mistakenly called ''coral insects," 

 are the animals that build up the coral reefs. In front of the window is a 

 life-size model in glass of the beautiful Portuguese Man-of-War. This 

 organism is really a colony of many polyp individuals attached to one 

 another, and specialized for various functions. 



The best known species in this group include the tapeworms, whose 

 Alcove 4 development and structure are showm by models in the 



Flatworms central case and in the third section of the left-hand alcove 

 case. These are parasitic Flatw T orms. The less familiar free-living 

 flatworms, wmich inhabit both salt and fresh water, are shown on an 

 enlarged scale by models in the right-hand alcove case and illustrate 

 well the great diversity of color and detail in this group. 



The Roundworms are also parasitic, since they live in the digestive 

 Alcove 5 canal of mammals. The most familiar is the common 



Roundworms roundworm or stomach worm, Ascaris, of which an en- 

 larged scale model is exhibited, showing the internal structure. 



[Note for teachers and students. — Some of the models in each alcove 

 are anatomical, i. e., so constructed as to show the internal organs of 

 typical members of each group. In such cases, arbitrary colors chosen 

 to designate the various systems of organs are adhered to consistently 

 throughout the series. For example, the digestive system is shown in 

 yellow, heart and blood-vessels in red, organs of excretion (kidneys) 

 in green, reproductive system in gray, and the brain and other parts of 

 the nervous system in black or neutral color.] 



The minute wheel animalcules comprise many exquisite and grotesque 

 Alcove 6 forms, some of which construct tubes of gelatinous sub- 



Rotifers stance, sand-grains, etc. A few of the species are parasites, 



but most of them live a free, active life. They are aquatic and found 

 mainly in fresh water. 



The sea-mats in Alcove 7 are plantlike animals which lead the 

 Alcove 7 colonial form of life. The majority of the species are 



Sea-Mats and marine, although a few occur in fresh water. The lamp- 

 Lamp-Shells s h e vig shown in this alcove superficially resemble clams, 

 but bv structure are more closelv related to the worms and starfishes. 



