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cover the whole of the surface of the spermatheca. 

 The spermatozoa have a narrow, slightly-curved head 

 and a long tail. The duct of the spermatheca is 

 narrow and thick-walled, and contains muscular fibres. 

 Certain large cells lie in connexion with the duct 

 externally. The mucus gland contains cells filled 

 with secretion. 



