116 Transactions. — Zoology. 



for a time, and then become more and more degenerate. The 

 large funnels of the genital segments become the funnels of the 

 vasa deferentia and oviducts. It will be observed that the 

 number of ovaries and oviducal funnels (two pairs) at first cor- 

 responds to that of the testes and sperm-duct funnels ; subse- 

 quently the gonads and commencing oviducts of segment xii. 

 atrophy. Each of these large funnels is continued into a 

 solid rod, which passes back through the septum, and then be- 

 comes continuous with a coiled tuft of tubules, in which there 

 is an evident lumen, and which is a part of the nephridium of 

 its segment. In the segments in front of and behind the 

 genital segments the rudimentary funnels communicate in the 

 same way with a solid rod of cells, which runs straight for a 

 short distance, and then becomes coiled and twisted upon 

 itself, and provided with a distinct lumen. In fact, apart from 

 the relative size of the funnels and the presence of the gonads, 

 it would be impossible to state from which segment a given 

 section through the terminal portion of a nephridium had been 

 taken. In a later stage the large funnels of the genital seg- 

 ments become ciliated, but this ciliation takes place before 

 there is any marked change in the tube which is connected 

 with the funnel. 



" In the young worm which has just escaped from the 

 cocoon the funnels are ciliated, and they are each of them con- 

 nected by a short tube, in which a lumen has been developed, 

 but which ends blindly in close proximity to a coil of 

 nephridia. No trace of any nephridial tube other than the 

 sperm-duct or oviduct could be observed, whereas in the pre- 

 ceding and succeeding segments the rudimentary nephridial 

 funnel, and a straight tube leading direct to it from the body- 

 wall, were perfectly plain. Dr. Bergh has figured, in his 

 account of the development of the generative organs of Lum- 

 bricus, a nephridial funnel in close contact with the funnel of 

 the genital duct. It may be suggested that a corresponding 

 funnel has been overlooked in the embryo Acanthodrilus : the 

 continuity of a structure, identical (at first) with the nephridia 

 of the segments in front and behind, with the genital funnels, 

 seems to show that a search for a small nephridial funnel 

 would be fruitless. 



"lean only explain these facts by the supposition that 

 in Acanthodrilus multiporus the genital funnels and a portion 

 at least of the ducts are formed out of nephridia. This mode 

 of development is a confirmation, to me unexpected, of 

 Balfour's suggestion that in the Oligochata the nephridium is 

 broken up into a genital and an excretory portion. 



"In the comparison of the facts briefly described here 

 with the apparently-independent origin of the generative ducts 

 in other Oligochceta, it must be borne in mind that in Acantho- 



