LEFEVRE. Vou. XIV. 
410 
organ; these cells would, therefore, have already possessed a 
ganglionic nature, and would merely resume in the bud their 
former function. 
On any such assumption, it is almost impossible to imagine 
how isolated specific cells, moving freely about in the blood, 
- could reach their proper destination. On the reverse assump- 
tion, however, the presence of these cells at any particular 
point is accidental, but, once there, their potentialities are 
called out under the specific formative influence of the place 
of attachment. 
BALTIMORE, MD., 
April 18, 1896. 
APPENDIX, 
Since the foregoing was written an article by Prof. W. E. 
Ritter has appeared in this journal (Vol. XII, No. 1) on the 
budding of Goodsiria and Perophora. Of the interesting account 
given of the budding in the former genus I have nothing to 
say, but, as the results which he has obtained from his study of 
the process in Perophora differ in some particulars from my 
own on the same genus, I desire to add another word. 
After reading his paper I again examined my sections with 
exceptional care under an oil-immersion lens, but am more 
firmly convinced than ever that the origin of the pericardium 
and dorsal tube and ganglion, points on which Ritter and I 
disagree, is that which I have described above; and that these 
structures in Perophora viridis, at all events, do arise solely from 
free amoeboid cells of the blood. Iam confident that in the 
form I have studied no cells are given off directly from the wall 
of the inner vesicle to the rudiments of the organs in question, 
as no cell proliferation can be observed, and never is there the 
slightest interruption in the boundary line of the wall. 
Although the peculiar rotation or transverse shifting of the 
inner vesicle, which I have described as occurring in Perophora 
viridis, does not take place to as great an extent in P. annectens, 
it nevertheless is found, and in this respect Ritter has fully 
confirmed my observations. Some time before the appearance 
