162 Proceedings of Boy al Society of Edinburgh, [april 4> 
invaded by glandular substance. In fully mature individuals the 
clitellum was perfectly developed on the ventral as well as on the 
dorsal side of the segments pertaining to it. A remarkable fact 
about the clitellum of this species is that the glandular substance 
is entirely undeveloped between the segments, so that this region 
of the body is just as plainly segmented as any other region; 
indeed, the contrast between the thick glandular appearance of 
the segments themselves, and the deep furrows which separate 
them, renders the segmentation if anything rather more conspicuous 
than elsewhere. 
It is to be noted that the number of segments occupied by the 
clitellum and their position is the same as in the other two species 
of Urochceta. 
The disposition of the setce is remarkable ; in the anterior 
segments of the body, comprising the first eight segments, the setae 
are arranged, as in Lumbricus , in four series of pairs ; the two setae 
of each pair are closely approximated to each other, and the 
intervals between the pairs are not widely different. 
In the 9th segment there is already some little difference in 
the setae ; the two setae of each of the ventral pairs are at a little 
greater distance from each other than in the preceding segments ; 
the dorsal pair of setae of the right side is completely similar to 
the same pair of setae in the foregoing segments ; on the left side, 
however, the two setae have become widely separate, the distance 
between them being much greater than that which separates the 
individual setae of the ventral pairs. 
In the next segment the two setae of each of the ventral pairs are 
somewhat more widely separated from each other, but the two setae 
of each of the dorsal pairs are again quite close together, as in the 
earlier segments. 
In the next few segments the two ventral pairs of setae remain 
exactly as in the segments just described; the innermost setae of 
the dorsal pairs correspond exactly in position to the innermost of 
the same pair of setae in the earlier segments. The outermost setae, 
however, vary very much in position, being sometimes nearer to, 
and sometimes further away from the innermost setae ; moreover, 
the two halves of the body are not symmetrical in this respect. 
Throughout the greater part of the body, commencing shortly 
