MORPHOLOGICAL STUDIES. 
159 
Weg den die parallelen seitlichen Strange des Bauchmarks 
durclilaufen haben miissen, um zum mediauen Riicken- 
marksrohre zu werdeu, scheint mir durcli die mitgetheilten 
Thatsachen aus der Entwiekelungsgeschichte der Anneliden 
selbst hinreichend klar vorgezeichnet. 1 Noch mebr. Aucb 
die Spinalganglien diirften ihre Horaologie bei den 
Anneliden finden, und zwar in den Parapodialgan- 
glien. Dreht man die tig. 47, Taf. xi, 2 um, so wird die 
Uebereinstimmung nicht entgeben. Der Unterschied liegt 
nur darin, dass die Spinalganglien bei ihrem Auftreten dickt 
am Riickenmarksrohr liegen oder in dasselbe eingezogen siud. 
Die hintere Wurzel — das am besten gekannte Beispiel der 
Enstehung eines Nerven bei den Wirbelthieren — bildet sich 
gerade so wie der mediane Parapodial Nerv, und die vordere 
Wurzel diirfte dem Muskelnerven, der sich mit jenem zu 
einem Stamm verbindet, gleich zu setzen sein.” 
So much for the present from Professor Kleineuberg. In 
general terms the result of my researches is a confirmation of 
his views and comparisons. 
If any further excuse were needed for a reopening of the 
question of the origin of the ganglia in Vertebrates, one would 
not have to seek far for ample reasons for such a course. 
Just as I was completing the first part of this work, three 
publications appeared, all of which showed the state of uncer- 
tainty and vagueness in which these questions at present exist. 
Professor Gegenbaur (No. 21) has undertaken no investigations 
on the matter, but feels himself entitled to quote as final the 
observations of one or other of his pupils, those of Sagemehl 
(No. 56) more especially appear to him to be far away above 
suspicion. I shall later on have occasion to point out how 
1 In a subsequent paper I intend to demonstrate that the central nervous 
system is a paired structure which arises as two lateral plates of 
neuro-epithelium separated by a median ciliated groove, just as 
in Annelida. 
a I have reproduced this figure in Plate XIX, fig. 64. In my copy the figure 
has been turned through an angle of 180°, to bring it in the “Vertebrate 
position.” 
