~ 
new Species of Thamnodrilus. 155 
papillz, which surround one of or both of certain of the 
ventral pairs af setze. 
These genital papille (see also below, p. 159), though not 
very conspicuous, cannot be missed on a careful examination. 
They seem to be flat, and each one is associated with one seta 
of the pair only. On the posterior of the clitellar segments, 
viz., segments 20—24—nearly coextensive, therefore, with the 
tubercula pubertatis,—each papilla extends round the outer- 
most seta of the ventral pair only. It is circular in shape, 
and is greyish white centrally, with a blackish periphery. 
Papillee are also found on segments 16-19 inclusive, but 
their arrangement is in these segments a little different from 
that which obtains in segments 20-24, for in the anterior 
segments both of the ventral pair of sete: are surrounded by a 
papilla, the two coming into contact, so that there appears to 
be one papilla, and that of a figure-of-eight shape, surrounding 
the pair. Further forward still—namely, on segments 10 
and 11—are also papille, and those are figure-of-eight shape 
as in segments 16-19. There are two final remarks to be 
made about these papillee: firstly, their different character in 
different regions of the genital area, and, secondly, the fact 
that they are quite as well developed in one of the three 
specimens which showed them, which had no clitellum, as in 
the two others where the clitellum was fully developed *. 
I was quite unable to detect the external apertures of the 
spermathecz, the sperm-ducts, and the oviducts. 
The internal organs were not in a very good state of 
preservation, but it has proved possible to settle the cha- 
racters of most of those which are used for the distinction of 
the different species of the genus. As in many species the 
four intersegmental sépta dividing segments 6/10 are thickened 
and lie successively within each other, like a series of cups. 
In front of the first of these, however, is a thin and delicate 
septum, actually the first visible, and, as I believe, separating 
segments 5/6. This is apparently not a common arrange- 
ment in the genus, since Cognetti f especially calls attention 
to it in Th. beddardi. It was, however, very clear in one 
specimen, and less so—though, I think, present—in a second. 
As the specimen in which this septum was quite obvious was 
immature and had developed no clitellum, tubercula pubertatis, 
or genital papilla, I cannot be absolutely certain that it is of 
an identical species. It is noteworthy that the four strong 
* It must be pointed out, however, that this only applies to the 
clitellar area, for in the two, examples with a developed clitellum the 
anterior segments (including 10 and 11) were deficient. 
+ Loe. cit. p. 225. 
