OLIGOCHATA OF TROPICAL EASTERN AFRICA. 265 
The two sub-families are, in fact, distinguished by the 
median or paired character of the generative apertures alone. 
In the absence of any other characters it appears to me that 
the paired or unpaired character of the apertures in question is 
by no means a difference of first-rate importance. Even if we 
follow Michaelsen in separating as a distinct genus the Cryp- 
todrilid Fletcherodrilus on account of its median series of 
spermatothecz, no one would in all probability consider that 
genus to be worthy of being placed in a separate sub-family, 
nor, indeed, does Michaelsen propose anything of the kind. 
The median spermatotheca of Sutroa does not disguise its 
likeness to other Lumbriculide. And in general there are so 
many instances in the group of the Oligocheta of structures 
which are paired in one genus and unpaired in another, thata 
division so pronounced as that which Michaelsen proposes does 
not commend itself to me. 
There are two characters which seem to me to afford a more 
reliable means of subdividing this family into two sub-families, 
should such a step be regarded as necessary; as they both 
relate to structures which are highly characteristic of the 
genera in which they occur, more weight is to be attached to 
them. The genus Eudrilus, when it was the only Eudrilid 
known, was shown by myself to differ from all other earth- 
worms by the possession of ventral median unpaired pouches, 
which Michaelsen termed ‘‘ Chylustaschen.” The fact that 
these structures are unpaired is not alone a fact that is greatly to 
be valued, though it may be pointed out that Gordiodrilus is 
at present the only other genus (not a Eudrilid) in which these 
so generally present, and with these exceptions paired, struc- 
tures are to be found. The most remarkable fact about these 
unpaired pouches is that they coexist with one pair of paired 
pouches not lying in the same segment as any one of them; this 
is more remarkable than if all the calciferous glands were paired 
or unpaired, as the case might be. Another (at that time quite 
unique) character of Eudrilus is the existence in the epi- 
dermis, or rather just below it, of numerous integumental bodies, 
which Dr, Horst and I myself have compared to the Pacinian 
