30 STUDIES OF AKIMAL LIFE. 



5. How do they differ in color ? 



What is the advantage of this difference ? 



E. The Girdle. 



The girdle is the broad band about the earthworm's 

 body near the anterior end and is concerned in 

 the formation of the egg case. 



1. Does it form a complete ring? 



2. Do all earthworms have a girdle ? How do you 



know? 



F. The Cuticle. 



The cuticle is the thin transparent covering of the 

 earthworm. 



1. Identify it. (Examine both dead and living speci- 



mens.) 



2. What is the color of the cuticle ? 



3. Observe (h.p.) small openings and very fine lines in 



the cuticle. 



4. Draw a small portion of the cuticle. (Use a pre- 



pared specimen.) 

 Can you suggest the use to the earthworm of such a 

 covering ? 



G. Blood-vessels. 



These are seen through the skin along the middle of 

 the dorsal and ventral surfaces. ' (To observe the 

 ventral vessel place the worm in a glass tube or on 

 a glass plate.) 



1. Do they extend the entire length of the body ? 



2. Observe the pulsation of the dorsal vessel. Is it 



regular ? 



3. In which direction does the pulsation move in your 



specimen ? 



