CONTRIBUTIONS TO THE ANATOMY OF THE HIRUDINEA. 483 



Fig. 6. — Clepsine. Diagram of a nephridium. a. Funnel. 6 — e. Testis 

 lobe. e—e. Main lobe. From e, through /, to the apex y, and 

 back througliyto e, runs the recurrent duct ; this then passes through 

 the main lobe to k, wliere it runs across to the apex ff. ^—/corresponds 

 to the apical lobe of Hirudo : from / the duct runs across to e, where 

 it re-enters the main lobe ; at k, it emerges and passes as efferent duct 

 to /, the external aperture. 



A B, CD, B F and G H. Sections through the regions so marked. «, n. 

 Nuclei. Tlie section c d is taken a Utile to the right hand of the 

 line c D. 



Section a b is a cell of the main lobe with its nucleus n, and contains 

 branching ductules ; and in addition to these, it surrounds in two places 

 perforated cells containing the duct in two subsequent portions of its 

 course, also showing nuclei, n, «, in their walls. 



Section c d shows two perforated cells in juxtaposition, each containing 

 a portion of the recurrent duct ; the one as it goes to, the other as it 

 comes from, the apex. 



Section e f shows the single perforated cell which contains the duct in 

 that portion of its course. 



Section G H shows the similar, but larger cell containing the efferent 

 duct. 



