34 Proceedings of the Royal Physical Society. 
The nephridia of this worm are paired organs. From and 
including the second segment of the body, the nephridia open 
by a large muscular sac. This sac appears to be capable of 
contraction and expansion, as in the nephridia of some 
segments the lumen was almost obliterated; in others, on the 
contrary, it was very spacious. In the case of the nephridia 
of the ivth segment, the terminal sac was greatly reduced, 
and the external aperture (in longitudinal sections) in con- 
sequence very inconspicuous. Nephridia are present in all 
the genital segments. . 
The dorsal vessel is single. In segments x., x1, xi. are 
dilated hearts. In the intestinal region the dorsal vessel 
gives off in each segment two pairs of branches, which 
supply the intestine; the dorsal vessel is here clothed with a 
layer of peritoneal cells, which are also continued on to its 
branches. Like those covering the intestine, they are 
vesicular in appearance and but little stained. I observed 
no subneural vessel. 
The alimentary canal is entirely without gizzard or 
calciferous glands—a state of affairs commonly met with in 
small, often aquatic, Oligocheta, whose nearest relatives are 
comparatively large terrestrial forms. The same is the case, 
to quote one example from several, with Pontodrilus, a near 
ally of the present species. Pontodrilus, however, is not 
always so destitute of a gizzard as is the worm which forms 
the subject of the present communication. In Pontodrilus 
littoralis the muscular wall of the cesophagus is thicker in 
one particular region than it is elsewhere. In Jicroscolex 
nove zelandie the longitudinal muscular layer of the ceso- 
phagus in segment v. is rather more pronounced than in any 
other part of the cesophagus; this region is also wider, and it 
seems undoubtedly to represent the gizzard of other forms. 
As, however, the epithelium which lines this part of the 
cesophagus does not differ in appearance from that which 
lines the rest of the tube, and as there is no chitinous layer 
thrown off by this epithelium, this part of the cesophagus 
cannot be termed a gizzard. In segments xi., xii., and xiii. 
the cesophagus is widened out in each segment, but con- 
stricted where it passes through the septa. The intestine 
