422 WILSON. [Vot. III. 
in Clepsine, and is likewise formed by the proliferation of a pair 
of teloblasts that arise directly from the ectoblast. I asserted 
in this paper (which was written before I had seen the works 
of Vejdovsky and Meyer) that the funnel arose in the peri- 
toneal mesoblast, independently of the glandular tube which was 
formed as an outgrowth from the nephric cord and must there- 
fore be of ectoblastic origin. 
From the foregoing review it appears that there is still a very 
wide divergence of opinion in respect to the origin of the nephridia, 
Bergh representing one extreme (which agrees with the earlier 
accounts of Kowalevsky and Hatschek) according to which the 
the entire nephridium (in Crtodrilus ) is mesoblastic; Whitman, 
representing the opposite extreme, asserting the origin of the 
entire organ from the ectoblast ; while Vejdovsky and Meyer 
agree in asserting the double origin of the nephridia; though 
they differ in some very important details. I pass now to a 
description of my own observations on Lumobricus. 
I have not specially studied the larval organs or “Schluck- 
zellen,’ and can give no additional facts in respect to their 
structure and mode of origin. As stated at p. 402, I have failed 
to find them in Z. fetidus, though they are easily demonstrable 
in ZL. communis and in L terrestris. It seems not improbable 
that their absence in ZL. o/¢dus may be correlated with the pres- 
ence of the peculiar glandular (?) thickening of the ventral lip 
of the stomodzeum described at p. 413; but I have failed to find 
the slightest indication of any excretory function in this struc- 
ture. In the other two species the remains of the “ Schluck- 
zellen”’ can be observed up toa comparatively late period (e.g. in 
the stages shown in Figs. 79, 80), though much diminished in 
size, lying as a granular mass between the entoblast and ecto- 
blast a considerable distance behind the cephalic cavity in the 
median dorsal line. 
As regards the “ provisional” excretory organs, or head-kid- 
neys, my observations are very unsatisfactory. They can be 
clearly observed in living embryos of ZL. communis at about the 
stage of Fig. 48 as a pair of very delicate longtitudinal tubes 
lying apparently on the dorso-lateral wall of the archenteron, 
extending forward at the sides of the stomodzeum and lined by 
actively vibratile cilia. In section (Fig. 92) they appear to be 
actually embedded in the wall of the archenteron, whence they 
