526 FRANK E. BEDDARD. 
pore represents the rudiment of nephridia. There are no 
special sperm-ducts present; only the nephridia of the 6th 
segment seem to be slightlye nlarged. Dr. Stole observed the 
spermatozoa to pass out of the body by all the nephridia, 
especially by those of the 6th segment, which are figured in 
his paper as slightly different from the rest. During the 
sexual period the nephridia in certain segments disappear 
either wholly or in part. There appears to be no formation of 
genital sete; these at least are not figured. 
M. Roule has discovered something of the same kind in 
Enchytreoides minimus (26). In this worm the first eight 
segments contain no nephridia at any time ; those of the 9th, 
10th, and 11th segments appearing only to disappear when the 
sexual organs are developed. The 12th segment possesses no 
nephridia, and it is not until much later that the sperm-ducts 
arise where the nephridia should have been; they are not pre- 
ceded by nephridia, but may be regarded perhaps as equiva- 
lent to a pair of nephridia somewhat delayed in their develop- 
ment. Inasmuch, however, as there is no conversion of un- 
doubted nephridia into undoubted genital ducts, the homology 
in this case could only be regarded as probable. 
My own facts, which have been described in some detail 
above, seem to show that in Acanthodrilus multiporus, at 
any rate, the funnels and a portion of the actual ducts them- 
selves of the vasa deferentia and oviducts are formed out of 
the nephridia. Balfour’s suggestion (‘Comp. Embr.,’ vol. ii, 
p- 617) that “in the generative segments of the Oligocheta 
the excretory organs had at first both an excretory and a 
generative function, and that, as a secondary result of this 
double function, each of them has become split into two parts, 
a generative and an excretory,” is thus confirmed in a way, 
which is to me most unexpected. We have in each segment 
to begin with a single pair of nephridia; in the genital seg- 
ments a portion of these nephridia is used to form the genital 
ducts, the rest retaining its excretory function. 
I have not had material which permitted me to trace the 
growth of the vasa deferentia to their point of opening on to 
