NOTKS ON THE JTl STRIOHDELLID.E. 
215. 
where it beiuls round and runs inwards and forwards below 
the intestine to form a loop (hgs. 8 and 9), which approaches 
near to or even meets that of the opposite side in a space 
between the intestine and nerve-cord, bounded laterally by a 
pair of almost vertical septa and separated from a space 
immediately overlying the nerve-cord by a horizontal septum. 
The returning limb of the loop is dorsal and, further back, 
internal to the other ; it runs back, and is traceable as far as 
a point nearly opposite the third cirrus and about half way 
between the lateral border and the middle line. Its external 
aperture on the ventral surface must be a little behind the 
third cirrus, but the absence of cilia in the terminal part makes 
it difficult to fix this point definitely, and this part of the 
nephridium, owing apparently to the crowding produced by 
the presence of the reproductive apparatus, is extremely hard 
to follow even in the best series of sections. 
In the male the trunk portion of the third nephridium forms 
a loop which does not extend as far forward as the penis and 
seminal vesicle. The returning limb of the loop, which may 
be twisted on itself, passes towards the ventral side and the 
eilia terminate a little distance behind the base of the third 
eirrus. 
The above account of the nephridial system of S. novae- 
hollandife differs in certain important points from that which 
I have previously described as the arrangement in S. tas- 
manicus — particularly as regards the first and second pairs. 
Whether these discrepancies are due to actual differences in 
the two species, or, as seems more probable, to misintei’preta- 
tion of the appearances previously observed, can only be 
determined by the re-examination of the Tasmanian species 
in the living condition. 
The differences between the nephridial system of Histriob- 
della as described by Foettinger (3) and more recently and 
more fully by Shearer (9), and that of Stratiodrilus are of 
a very marked character. In the former the system does not 
extend either into the head or into the tail, and the three ( $ ) 
or four ((d' ) pairs of tubes of which it is composed are simple. 
