ON THE NEMATODES OP THE COMMON EAR'L'HWOEM. 611 
(2) The Active Form living free in the Nephridia. 
The nephi’idial foi’m inhabits the cavity of the “bladder,” 
the dilated muscular termination of the nephridial tube next 
to the uephridiopore. It occurs very constantly in worms of 
this pai’ticular species. Several are to be found in almost 
every nephridium. The number present varies from two or 
three to over a dozen. The nematodes are found in worms 
of all sizes. The largest and most healthy-looking appear to 
be infested quite as much as the weakly specimens. I have 
seen the nematodes in worms which are only 1'5 in. long and 
are so young as scarcely to be recognisable as Lumb. 
terrestris. The only part of the nephridium in which the 
nematodes occur is the bladder. On one occasion, certainly, 
I saw one in the “wide tube,” but it had evidently strayed 
from the bladder and it soon went back. 
The active form is sometimes met with in the seminal 
vesicles (5, p. 11). 
I have examined other species of earthworms besides 
Lumb. terrestris, and have found the nephridial form 
present in Lumb. rubellus Hoffmeister, Eisenia foetida 
Savigny, Dendrobaena snbrubicunda Eisen, and Octo- 
lasium cyaneum Savigny. They are in some cases 
plentiful, as they are in Lumb. terrestris. But the}" are 
more often present in only very small numbers, and most 
frequently absent altogether. The nephridial form in Oct. 
cyaneum belongs to the same species as that in Lumb. 
terrestris. I have not identified those found in the other 
species of earthworms, but I believe them also to be the 
same. 
The nephridial form is in an active condition, though it 
may exhibit very varying degrees of activity. It often 
remains coiled and motionless or makes only sluggish move- 
ments. At other times it writhes unceasingly. Like the 
coelomic form it is always found in a larval, never in an adult, 
state in the freshly killed worm. Like the coelomic form, too, 
it varies considerably in size and stoutness of build, but the 
