EARTHWORM 61 



See that the watch glass is carefully covered. Change the 

 water at each laboratory period. Make observations on struc- 

 ture and movements of each piece until regeneration is completed. 

 Make outline drawings of each piece as often as directed at the 

 beginning of each laboratory period before taking up the ad- 

 vanced work of the day. Record the date of each set of draw- 

 ings. 



After this experiment is completed write a connected account 

 of regeneration as it occurs in Planaria. 



REFERENCE 



Morgan, T. H., 1901. Regeneration. Mac M Ulan Co. 



EARTHWORM 

 (Lumbricus terrestris) 



(Materials: tags, pins, jars with formalin and covers, 

 pipettes.) 



Classification: Phylum Coelhelminthes, Class Annelida, 

 Order Oligochaetae. 



There are numerous species and genera of earthworms. The 

 one chosen for this study is not a native of this country but was 

 introduced from Europe and has become established in some lo- 

 calities. The small worms which are found in the soil and on 

 walks after heavy rains are usually not the young of this same 

 species but represent a number of separate genera and species 

 differing considerably in internal structure. Information given 

 in this outline does not apply to all earthworms. 



I. EXTERNAL CHARACTERS 



i. Note that the body is composed of a series of similar 

 rings placed end to end. Each of these divisions or rings is 

 called a somite or segment. Notice that the body is almost cyl- 



