THE GIANT EARTH-WORM OF GIPPSLAND. Al 
small nephridia, the latter alone present at the anterior end of the body, whilst both 
are developed in each segment posteriorly. The latter only have ciliated funnels 
opening internally. Each consists of two distinct portions, in one of which the duct 
is tracellular, in the other the duct is intercellular, and opens to the exterior. The 
latter may be supposed to represent the more highly developed nephridial opening 
with vesicular portion present in other worms. In the larger nephridia, a third part 
is present at the intercellular opening of the nephridial funnel into the ccelom. This 
may in various worms be of greater or less extent, but in Megascolides appears to be 
very small. In A. multiporus,* Bspparp describes an aggregation of the nephridial 
tubules into eight definite tufts, one corresponding to each seta in the hinder part of 
the body. In some cases two nephridiopores correspond to a single seta. The 
aggregation is not quite perfected, as “occasionally a single tubule was observed to 
perforate the body wall between the sete” in positions corresponding to septa of 
connective tissue, which break the continuity of the longitudinal muscle layer. 
Bepparp suggests that such septa represent the last trace of setee, which have now 
disappeared. These irregularities are interesting, as showing that the present 
condition of the nephridia in the posterior part of the body in A. mwultiporus is due to 
an aggregation ot the nephridial tubules, each tuft connected with a seta being the 
result of a massing together of a certain number of nephridial tubules to form one 
mass, as evidence of which may be instanced the occasional presence of more than one 
nephridiopore. In Megascolides, the differentiation has been at once carried further, 
and along somewhat different lines, and it must be noticed that the differentiation in 
- both A. multiporus and Megascolides commences in the posterior region of the body— 
a point of importance when we come to consider the relationship of the nephridia to 
the genital ducts. 
In Megascolides, the small nephridia are very much more numerous in the 
anterior part of the body than in the posterior; but side by side with this, a secondary 
development of large nephridia has taken place in the latter. If we examine the 
nephridia in situ we find, as previously described, that the large ones are only present 
in the anterior half of the last hundred or so segments of the body, a ring of smaller 
ones being present in the posterior half of each segment. In the middle region of the 
body, the large nephridia can for a certain number of segments be distinguished, but 
with no internal openings, and gradually come to form one of a group of nephridia 
slightly larger than the rest. Passing forwards, the single one becomes less and less 
distinguishable in size from the other members of the group of which it thus forms one, 
*I cannot tell from Brepparp’s paper whether the Acanthodrilus described there is the same form 
which he had previously described in the P.R.S. (No. 238. 1885) as possessing eight nephridia in each 
segment—one corresponding to each seta. Both worms came from New Zealand. In the first paper the 
nephridia are described as being single structures, in the second as being tufts of nephridial tubes, the 
external orifices of which are, as a general, though not universal, rule, associated with the sete. If they 
are not identical forms, it is very interesting to see the aggregation perfected in the first worm described, 
with the result that one definite nephridium corresponds to each seta. 
G 
