17(S Transactions. 



nephridia which open on the dorsal snrface are placed dorso-laterally ; 

 those which open on the ventral, ventro-laterally. The fnnnels, however, 

 are all placed ventrally, in line. This condition has been described by 

 Benham for M. uliginosus, and may be contrasted with that of the genera 

 described by Hubrecht and Borelli, where there is only ene position of the 

 nei^hridia corresponding to three positions of the external pore. This 

 2:»osition is ventral, and the terminal duct, in order to open dorsally, runs 

 up between the muscular layers from the ventral to the dorsal surface. 



In Maoridrilus rosae the terminal bladder opens directly to the exterior 

 (at the points ne.f.d, ne.p.v, fig. 2). In general arrangement and position 

 in the body-cavity they are very similar to the nephridia of Neodrilus 

 monocysiis as figured in a transverse section by Benham (11), pi. 15, fig. 4, 

 and m M. idiginosus (12). It is probable that in both worms their minute 

 structure is similar to that of M. rosae. 



The nephridium of Maoridrilus is formed essentially on the same plan 

 as that of Lumbricus, although the former is somewhat simpler in structure, 

 and differs in external appearance from the latter. Lumbricus has only 

 one series of nephridia, which are therefore all alike ; but in Maoridrilus, 

 as in several New Zealand earthworms, the two series exhibit slight dif- 

 ferences of form in accordance with their position. The chief difference 

 between the dorsal and ventral series (see fig. 2) concerns the terminal 

 bladder (bl). In the ventral nephridia this has a large caecum directed 

 dorsally, while in the dorsal series the caecum is smaller, the bladder being 

 continued only a little way beyond the external pore. 



The nephridium is made up of a small preseptal and a large post-septal 

 region. The preseptal portion (fig. 2) consists, as usual, of a funnel, a 

 nephrostome, and a funnel-duct, lying more or less parallel to the septum, 

 with its opening directed upwards. The preseptal part of the nephrostomial 

 duct is a delicate tubule which curves round from the funnel, passes 

 immediately through the septum, and joins the post-septal portion of the 

 nephridium. 



TJie Funnel. — It is by no means easy to dissect out a nephridial funnel 

 in this species, owing to its position close against the septum, and its 

 proximity to the nerve-cord, so that its structure was studied chiefly in 

 sections. But I was able to obtain a good view of one sufficiently isolated 

 to exhibit its general form ; and it will be noted (fig. 3) that the marked 

 dift'erence in the height of the dorsal and ventral lips which is familiar to us 

 from the usual figures of the Lumbricus nejihrostome is here absent.* 



The funnel is not distinctly marked oft" from the funnel-duct, which is 

 at first nearly as wide as the funnel itself, and slowly tapers towards the 

 septum (fig. 4), which it perforates. The large lateral flaps formed by the 

 prominent rounded lip in Lumbricus, &c., are here absent, and at a first 

 glance the whole preseptal portion looks like a very long funnel ; but 

 further study shows that this really consists of the true nephrostome and 

 its preseptal duct. 



The actual opening is comparatively wide, and surrounded by a rathej- 

 thick ciliated lip, formed by marginal cells. The thickness of this lip is 

 almost uniform all the way round, except that it is interrupted on the ventral 

 surface ; though in the figure this margin is shown as it actually appeared 

 in the preparation, undulating, so that the height of the lip appears to be 



* Reference may be made to Benham's figure of the nephrostome of Micror.haefa 

 i2)jn. in which also the lips are quite ill defined (8). 



