48 LUMBRICUS TERRESTRIS. 



Exercise 5. Draw one of the cocoons or egg-sacs of the Earthworm. 

 These may be secured by digging among their burrows in the early 

 summer. 



HINTS ON COLLECTING. Earthworms are most abundant in the 

 rich soil of old gardens and lawns and along the banks of ditches or 

 drains. They can be secured by digging at almost any time in the 

 spring or summer. Some collectors prefer to search for them with a 

 lantern on warm, rainy nights, when they may be found with a part of 

 the body, at least, protruding from the burrow. When searching in 

 this way the collector should go about quietly and not allow the light 

 to shine too long on one spot. The worms having been secured by 

 either method, take them to the laboratory and place them between 

 moist sheets of blotting paper or filter paper in covered dishes of some 

 sort. Keep them there a day or two, changing the paper every half 

 day. Do not put more than a dozen in the same dish. They will soon 

 have eaten enough of the moist paper to clean the alimentary tract of 

 earth. If they are to be preserved place them now in 4 per cent 

 alcohol and gradually increase the strength to 8 per cent by adding a 

 little alcohol at a time for the next few hours. After washing them in 

 water to free them from mucus place them in fresh 8 per cent alcohol 

 until they are dead. Now put them in 50 per cent alcohol for four 

 hours and then in 70 per cent for twice that length of time. Harden 

 them in full strength alcohol for a day and then return to the 70 per 

 cent for final preservation. Keep them as straight as possible during 

 these processes. 



In the American Naturalist, November, 1905, is given an excellent 

 method of preserving Earthworms by means of chromic acid. Speci- 

 mens preserved in this way are in better shape for dissecting than those 

 preserved by the alcohol method. 



