No. 3.| ZHE EMBRYOLOGY OF THE EARTHWORM. 425 
though, owing to the fact that the nephric cords are somewhat 
wider than the nephridia themselves, this connection will not be 
seen, unless the section pass precisely through the right point, 
as shown for example in Fig. 86. To this fact is due, as I 
believe, Bergh’s failure to observe the connection of the nephric 
rudiments with the ectoblast. I shall not undertake to explain 
this author’s very positive statement (which is made the text of 
an extravagant critique of my own work), that the ectoblast is 
one-layered outside the nephric rudiments, until I have had 
an opportunity to examine for myself the development of these 
organs in Cyviodrilus, a subject which apparently needs re-inves- 
tigation. 
The appearances I have described irresistibly suggest the 
interpretation given in my former paper, viz.: that the funnel 
and the investing cells alone are mesoblastic in origin, the body 
of the nephridium being derived as an outgrowth from the 
nephric cord. This conclusion is supported by Whitman’s 
observations on C/epsine, where the peculiar granulation of the 
nephric cells and their behavior with certain reagents renders 
the development of the parts even clearer than in Lamoricus. 
It fits in, moreover, completely with Meyer’s observations on the 
Polychzeta, as far as they go. The “retroperitoreal’”’ tissue of 
this author (which he is careful to distinguish from the perito- 
neal mesoblast) corresponds exactly with the tissue from which 
the nephric rudiments arise, having the same relations to the 
investing cells and to the funnel. Unfortunately he has not 
yet determined its origin, and until this all-important question 
is answered, the nature of the glandular part of the nephridium 
cannot be established. It is, however, interesting to note that 
in Psygmobranchus, as in Lumbricus, the nephric foundations 
alternate regularly with those of the setigerous glands (cf: No. 
36, Taf. 23, Fig. 2), apparently forming with them a continuous 
series, and it seems hardly too much to venture the prediction 
that they will be found to have a like origin. 
As regards the origin of the glandular portion of the nephrid- 
ium in Lumbricus: from the numerous preparations in my 
possession, I should still have no hesitation in positively reas- 
serting my original statement as to its ectoblastic origin, were 
it not for Vejdovsky’s careful observations on other Oligocheta, 
which seem to be opposed to such a conclusion. In view of 
