1885.] Nephridia of a New Species of Earthworm, 



459 



XIV. " Preliminary Note on the Nephridia of a New Species of 

 Earthworm." By Fraxk E. Beddard, M.A., F.R.S. (Ed.,) 

 Prosector to the Zoological Society. Communicated by 

 Professor E. Ray Lankester, M.A., LL.D., F.R.S. Received 

 May 19, 1885. 



The specimens upon which the following observations are based 

 I owe to the kindness of Prof. T. Jeffrey Parker, of Otago Uni- 

 versity ; I received from him a large number of examples of an earth- 

 worm which appears to belong to Perrier's genus, Acanthodrilus* 

 though differing from any of the species of that genus as jet described. 

 In the present paper I do not intend to describe the general anatomy 

 of this worm, but to refer merely to the disposition of the " segmental 

 organs " or nephridia, which present certain interesting peculiarities 

 which have not, to my knowledge, been recorded in any other earth- 

 worm. 



Each of the segments of the body in this species, instead of pos- 

 sessing only a single pair of nephridia, is furnished with four pairs, 

 a single nephridium corresponding to each of the eight setae ; the 

 setae are not disposed in four series of pairs as in Lumbricus, but in 

 eight longitudinal rows of a single seta, each separated by nearly 

 equal intervals. Cn making a dissection of a large example (12 inches 

 in length) it was quite easy to observe the two nephridia of the dor- 

 sally placed pair of setae, and to trace by help of a lens the duct which 

 perforates the body-wall in the immediate neighbourhood of the setae ; 

 each of these nephridia appeared to be quite distinct from its neigh- 

 bour ; the nephridia belonging to each of the ventrally placed pair of 

 setae, on the other hand, form a continuous mass closely adherent to 

 the intersegmental septum. 



On making a series of transverse sections the appearances observed 

 by a naked-eye inspection were confirmed ; a nephridial tube per- 

 forates the body-wall and opens on to the exterior in the neighbour- 

 hood of each of the eight setae. In every case the nephridium passes up 

 close to the seta and is imbedded in the loose connective tissue which 

 tills up the gap in the longitudinal muscular coat partly occupied by 

 the seta and its special muscles. At the junction of the longitudinal 

 and the outer, circular, muscular coat the tube bends at right angles 

 and passes in a direction parallel to the fibres of the circular coat, but 

 below it, i.e., between the two muscular coats ; this portion of the 

 nephridial tube is considerably longer in the case of the extreme 

 dorsal nephridium — about three times as long. The tube then passes 

 in an oblique direction through the circular coat and opens on to the 



* "Jfouv. Arch. d. Museum," t. yiii. 



