EEPRODUCTIVE SYSTEM 49 



d. The epididymes are a pair of convoluted tubular 



bodies with thick white walls, lying in the sixth 

 somite. They secrete a substance by which the 

 spermatozoa are aggregated into spermatophores. 

 From the inner side of each a short duct leads 

 to the base of the penis, the duct of the right side 

 passing under the nerve-chain. 



e. The penis is a pyriform body lying in the sixth 



somite. It is wide at its base, narrow and tubular 

 in its distal part, and can be protruded some dis- 

 tance through the male genital aperture in the 

 second annulus of this somite. 



2. The female organs lie entirely in the seventh somite. 



a. The ovaries are a pair of minute filamentous bodies 



enclosed in small spherical ovisacs, and lying 

 close to the mid-ventral Jine. 



b. The oviducts are a pair of slender tubes leading 



from the sacs of the ovaries, which unite to form 

 a much convoluted duct surrounded by uni- 

 cellular gland cells, and opening into the vagina. 

 The right oviduct passes under the nerve-chain. 



c. The vagina is a thick- walled muscular tube, opening 



to the exterior at the female genital pore in the 

 second annulus of the seventh somite. 



E. The Nervous System. 



The nervous system consists of a pair of supra- oesophageal 

 ganglia, a nerve collar, and a double ganglionated cord ex- 

 tending the whole length of the ventral surface. From the 

 ganglia nerves run outwards to the various parts of the body. 



1. The supra-oesophageal ganglia are a pair of closely 



apposed bodies in the dorsal wall of the anterior 

 end of the pharynx, immediately behind the jaws. 

 They supply the jaws, the eyes, and other parts of 

 the anterior end of the body. 



2. The nerve collar is very small, and closely surrounds 



the anterior end of the pharynx. 



