124 THE BIOLOGY OF THE ANIMAL 



side ? How ? "What is the length of the speci- 

 men examined? Where is the circumference 

 of the body greatest? Where least? What is 

 the shape of a cross-section of the body made 

 through the largest part ? 

 Make an outline drawing, twice natural size, of the 

 worm seen from above, and of the cross-section. 



h. Color. — What is the general color of the body ? What 

 differences in different regions? Can you give any 

 reasons for these differences ? 



c. Oeneral structure. — Into how many distinct regions 

 may the body be divided ? Do these regions 

 have any characters in common ? How many 

 segments or somites in each region? Is the 

 number constant ? Compare several specimens to 

 determine. How do you distinguish one somite 

 from another ? Does the individual segment bear 

 any markings ? Where is the most muscular part 

 of the body, as determined by the firmness of the 

 body-wall ? How many segments in this portion ? 

 How do they compare in size with those of other 

 regions ? In color ? What is the number, count- 

 ing from the front, of the largest segment of the 

 body ? Of the smallest ? Do you find any seg- 

 ment which is not a complete ring ? Has the 

 body any protective covering or exoskeletou ? 

 Are there any jointed appendages, e. g., legs, on 

 the body? Are there any respiratory organs, 

 e. g., gills, visible on the surface? Any organs 

 of hearing or of sight ? 

 On your outline drawing indicate the various regions, 



placing the exact number of segments in the first two 



regions. 



