352 ZOOLOGY 



light) and cut off side lights. Observe and record movements or lack 

 of movements. 



2. Place a Daphnia in a tube containing a single wad of algse; 

 place another Daphnia in a tube containing a small pebble ; observe 

 and record behavior with reference to the foreign body. 



3. (Optional.} Place an egg-bearing female in a Stender dish con- 

 taining bits of decaying plant. After seven days count the number of 

 individuals. Compare with the number in a similar dish kept (by 

 the teacher) for seven days in a cool place (5 to 10 C.). 



TOPICS FOR FURTHER STUDY 



1. The habitat and food of Daphnia. 2. Allies of Daphnia : Bran- 

 chipus, Cyclops, Cypridopsis, barnacles, trilobites. 3. The pupil should 

 learn to distinguish Daphnia, Cyclops, and the other Entomostraca in 

 the aquarium by their locomotion. 



IX. EARTHWORM (AllololopJiora or Lumbricus) 



Various species may be used. During the winter time, when the 

 ground is frozen, earthworms are best sought under compost heaps; 

 or they may be kept in laboratory in flower-pots containing rich, moist 

 vegetable mould and covered by a glass plate. They may be fed 

 upon fallen leaves placed in the pots. 



DRAWINGS 



(From alcoholic specimens) 



1. Whole animal, dorsal view, x 2. 



2. Head end, 6 or 8 segments, ventral view, x 5. 



3. Tail end, 6 or 8 segments, ventral view, x 5. 



4. Two adjacent middle segments, showing setae, x 5. 



5. Cross-section, showing position of setse. x 5. 



QUESTIONS ON EXTERNAL ANATOMY 



1. Count the number of segments of two or three individuals. 

 Are they the same? Inference to be drawn from the result? 



2. Where does growth in length take place? Evidence for your 

 conclusion ? 



