316 W. BLAXLAND BENHAM. 



Again, one species of Dinophilus has been described as 

 having a network of nephridial tubules ; and another species, 

 by Harmer, as having simple unbranched nephridia. 



It appears possible that the meganephric condition may 

 have arisen, as Spencer suggests (30, p. 43), either {a) by en- 

 largement and elaboration of one tubule of the network, or 

 {b) by an aggregation of a portion of the network. 



Spencer does not state which alternative he believes to 

 obtain in Megascolides, but probably the former, as he men- 

 tions no network in the large hinder nephridia, which he 

 implies are simple unbranched tubules. He remarks that it 

 would be impossible to map out the course of the tubules by 

 means of sections : this might, however, be done by examina- 

 tion of the whole nephridium, as I have done for Micro- 

 chseta; and I am inclined to regard the second alternative — 

 aggregation of a portion of the network — as the probable 

 mode of origin of the large nephridium (PI. XXV, fig. 42). 

 The tubule might become enlarged, lose some of its branches, 

 and thus present a looser network ; it would then become 

 differentiated into " wide" and "narrow" regions, and ulti- 

 mately lose all connecting tubules, so as to give rise to the 

 complicatedly coiled tube of Lumbricus, &c.; while 

 Microchgeta and Brachydrilus would represent the inter- 

 mediate stages with still some of the primitive network in 

 part of the course. 



Another intermediate condition appears to be presented by 

 the " peptonephridium" of Uroch83ta, which retains some of 

 the branches and three funnels, but has only one external 

 aperture. 



4. The Funnel of PERicHiETA malamaniensis, n. sp., 



AND SOME other GeNERA. 



In my earliest contribution to lumbricological literature 

 (8) I stated that a certain species of Perichseta from Mala- 

 mani, amongst the Philippines, possessed numerous small 

 nephridia in each segment with several funnels. I believe I 

 was the first zoologist to mention this multiplicity of nephridial 



