PROBLEM I. The Kinds of Ajii7nals of the Earth 71 



Make a collection of your own, using a shell book to learn the names 

 of the animals. By exchanging specimens you may he able to get shells 

 from other parts of the country. 



9. The complete story of Charles Darwin's study of the effect of the 

 earthworm on the soil is told in his book, The Fonnatioii of Vegetable 

 Mold. It is not difficult to read. Prepare a report for the class. 



10. If you follow directions carefully you can maintain a salt water 

 aquarium. Starfish, sea anemones, and mussels will live in it if you have 

 plenty of seaweed. A Turtox leaflet (General Biological Supply House, 

 Chicago, Illinois) will provide complete directions. You may buy the 

 plants, animals, and sea water from biological supply houses if you are 

 far from the coast. 



1 1. If you are talented in drawing prepare a mural for the walls of your 

 classroom, showing examples of animals in each of the phyla from the 

 sponges to the arthropods. 



12. If you have a good hay infusion and are skillful with the micro- 

 scope, make daily observations and keep accurate notes. Always take 

 samples of water from different levels in the jar. You will make an inter- 

 esting discovery in the course of several weeks. 



13. Have you ever thought of owning a microscopic pet? It is really 

 easy. Paramecia make the best pets because they are hardy. By heating 

 a piece of glass tubing soften it until it can be drawn out to make a very 

 narrow tube. Break this narrow tube so that you have a pipette with a 

 narrow opening. Put a slide containing paramecia on a piece of black 

 paper so that the paramecia can be seen with the naked eye. They will 

 appear as white specks. Catch one by dipping the pipette into the water 

 near it. Draw the pipette out quickly so that you catch only one para- 

 mecium. Gently blow the paramecium out on another slide. Add some 

 cool boiled hay infusion water. Then put the slide in a Petri dish (ask 

 your teacher). The Petri dish must contain a piece of blotting paper 

 soaked in water. This will moisten the air. To keep the bottom of your 

 slide dry, put it on two match sticks that lie on the blotting paper. Cover 

 the dish. The next day you should have two or more paramecia. Repeat 

 this process, discarding one of the animals, and keeping the other. 



