LABORATORY WORK, XI 355 



bottom is covered with damp moss ; they may be fed upon fresh 

 apples, cabbage leaves, etc. Limax maximus is to be preferred on 

 account of its large size. 



DRAWINGS 

 (From the living individual) 



1. Dorsal view, showing mantle, foot, respiratory opening, head and 

 tentacles, x 1.5 to 3. 



2. View of right side, x 1.5 to 3. 



3. Front view, showing tentacles, mouth, and lips of slime-gland, 

 x 3. 



OBSERVATIONS ON THE LIVING ANIMAL 



Each student should be provided with a pane of glass, 8 by 10 

 inches. 



1. Place the slug on the glass and study its locomotion from the 

 under side of the plate. Describe in the note-book what is seen. 



2. Place the slug on the glass plate, hold the plate vertical and 

 parallel to the window, the slug being horizontal and parallel to 

 one edge of the pane ; shield from lateral lights. Having made in the 

 note-book an outline to represent the plate, indicate in this the posi- 

 tion of the slug at the beginning of the experiment and at intervals of 

 ten seconds for about a minute. Repeat. A piece of planed board is 

 better than the glass plate, excepting that it cannot be kept so clean. 



3. Place the plate horizontal near a window and let the slug be par- 

 allel to the window. Do not let direct sunlight fall upon it. Plot in 

 the note-book, as before, the position of the axis of the slug at inter- 

 vals of ten seconds. Repeat. 



4. Note the reaction of the slug to contact on different parts of the 

 body : tail, head, antennae, edge of mantle. 



5. Does the slug react to passes of the hand ? To moisture ? 



, TOPICS FOR FURTHER STUDY 



1. The habitat, food, and methods of feeding of the slug. 2. Its 

 distribution. 3. The economic importance of slugs. 4. The shell of 

 the slug. 5. Allies of the slug : Helix, Pupa, Limnsea, Physa, Planor- 

 bis, Littorina, Fulgur, Fissurella, JBoli's, Chiton, the Nautilus, and 

 other cephalopods recent and fossil. 



