EXOEETOEY SYSTEM 65 



a. The funnel is ciliated, its border consisting of a row 



of large cells with very distinct nuclei. The 

 nephrostome or open mouth of the funnel can 

 be readily seen. 



b. The first part of the tube is very slender and 



difficult to make out : it lies alongside the inner 

 and middle of the loops formed by the wider 

 part of the tube. The canal of the tube is here 

 an intracellular one, traversing the individual 

 cells. 



c. The second part of the tube is much wider,, the 



change in diameter being abrupt, and the canal 

 having from this point proper cellular walls. It 

 runs up and down the middle loop of the three, 

 at the dorsal end of which it is considerably 

 dilated ; then up and down the shorter inner 

 loop ; and finally across to the outer loop, where 

 it forms the terminal portion of the tube. The 

 first portion of the tube is lined by a ciliated epi- 

 thelium ; the distal portion has glandular walls, 

 and is very vascular. 



d. The terminal portion of the nephridium is much 



wider than the rest : its walls are non-glandular, 

 and composed largely of interlacing muscular 

 fibres. It opens to the exterior by the aperture 

 already seen, in front of the outer seta of the 

 inner double row. 



E. The Eeproductive System. 



The earthworm is hermaphrodite. The reproductive organs 



are lodged in segments ix. to xv., i.e. in the region of the 



oesophagus. 



1. The female organs consist of a pair of ovaries ; a pair of 



oviducts, with a receptaculum ovorum opening into 



each ; and two pairs of spermathecae. 



a. The ovaries, which lie in segment xiii., are a pair 



of white pyriform bodies attached to the septum 



forming the anterior wall of the segment, and 



