ZOOLOGY OP FERNANDO NORONHA. 
561 
colour, somewhat like that of Lumbricus terrestris ; it measured 
5| inches ; the fifth turned out to be merely the anterior portion 
of a similar specimen. 
The Worm A . — The first feature which struck me was the 
quincuncial arrangement of the setae in the posterior region of the 
body ; anteriorly the setae are in couples. 
The body-wall, being somewhat transparent, allowed me to 
distinguish through it paired light-coloured bodies, or “pyriform 
sacs,” lying in the ventral region posteriorly. The most 
anterior somite of the body is very elongate, and carries the 
mouth terminally, the prostomium being absent. These features 
recalled the genus Urochceta of Perrier ; but somewhat similar 
characters are found in other Earthworms : thus the pyriform 
sacs have been described by myself in TJrobenus * ; and the scat- 
tered condition of the setae, though not identical with the arrange- 
ment noticed, closely resembled, and might easily be confounded 
with, what obtains in Diachceta (Beuhani). 
Turning then to the clitellum, I found it to cover the somites 
xiv. to xxii. or xxm. ; it is not complete on the ventral surface ; 
and both anteriorly and posteriorly is* as is often the case, 
more feebly developed. One peculiar feature, however, about 
the clitellum, which therefore recalled Urochceta, is the fact 
that the intersegmental grooves are deep and noticeable ; the 
glandular structure not being continuous from somite to somite, 
as is the case in most other Earthworms. 
I could see no pores, or external apertures, of the genital ducts 
or nephridia ; I therefore opened the worm, in the ordinary way, 
by a median dorsal incision, in order to satisfy my suspicion as 
to its belonging to the genus Urochceta. 
The septa are thin, with the exception of four situated anteriorly, 
which are greatly thickened, namely those forming the posterior 
wall of somites vi.,vii., viii., and x. (the septum between ix. and x. 
is absent). Such thickened muscular septa are not unusual in 
Earthworms ; but whether their position is constant in a given 
species is by no means certain. Perrier has not helped us to 
settle the matter, since in his figure he represents only four such 
septa, whereas in the text he speaks of five of them. Hohvever, 
Beddard t, in a species of this genus from Australia, describes four, 
having the same position as in the worm under consideration. 
* Quart. Journ. Mier. Sci. vol. xxvii. 
t Proc. Roy. Soc. Eclinb. xiv. 1887, p. 160. 
