240 
FEANK E. BEDDAED. 
elsewhere (1) urged is the primitive condition of the Anne- 
lid nephridium, or is the branching, as Dr. Eisig would 
argue (15), secondary ? This raises again the whole question 
of the derivation of the Annelid excretory system, to which 
Dr, Eisig’s recently published Monograph upon the Capi- 
tellidse is a most weighty contribution. 
In the latter part of this paper (p. 260) I discuss some 
general questions relating to the nephridial system of Earth- 
worms ; but it will be convenient to treat here of the argu- 
ments which the structure of the mucous gland of U rochseta, 
and of some other genera, furnish for the derivation of these 
glands from a continuous network of tubules. 
I have already stated that this gland in Urochseta com- 
municates with the coelom by three funnels ; I am not quite 
certain whether there is not a fourth. In any case there seems 
to be no doubt that the number of branches is in ex- 
cess of the number of ciliated funnels. Perrier’s 
figure of the organ (22, pi. xvi, fig. 35) is, so far as I can 
ascertain, accurate, in that it indicates the convergence of a 
large number of nephridial tubules to form the long duct 
of the gland. I have reason, however, to believe that in 
some cases the tubules unite before their opening into the 
muscular duct ; but this is not a matter of great importance. 
One of two things must therefore follow : either the tubules 
again unite before the ciliated funnels, thus forming a 
network, or a large number (the greater number) of the 
tubules end blindly without any coelomic apertures. I can 
find no evidence of the truth of the first supposition, and 
must therefore come to the conclusion that the mucous 
gland is a branched nephridium, of which the greater 
number of branches end blindly, while a few open 
into the coelom by ciliated funnels. 
These facts would seem to show that the gland is in some 
respects degenerate ; that it primitively possessed a larger 
number of ciliated funnels, the greater part of which have been 
lost. So far this is merely an assumption, which at any rate 
harmonises with the structure of the organ. Although the 
