258 ANNULATA 



(4) Sketch the nervous system of the earthworm. What is 



its use? 



(5) Special Senses. 



8. Excretory System. The Nephridia. Look for Httle white, 

 coiled tubes between the septa. 

 (1) Trace one. 



(a) Where does it open? 



(b) Use? 



C. Cross-section 



1. Dorsal Wall. 



(1) Cuticle — thin, iridescent. 



(2) Epidermis. 



(3) Dermis. 



(4) Circular muscles. 



(5) Longitudinal muscles. 



2. Coelom or Body Cavity. 



3. Dorsal Blood-vessel. 



4. Alimentary Canal. 



5. Ventral Blood-vessel. 



6. Nerve Cord. 



7. Ventral Wall. 



(1) Longitudinal muscles. 



(2) Circular muscles. 



(3) Dermis. 



(4) Epidermis. 



(5) Cuticle. 



Sketch this cross-section and show all the parts 1-7. 



