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de fibrilles tres minces mélées a une substanse finement ponctuée.« 
Whether he considers these fibrillæ to spring from the processes of 
the ganglion cells, he does not distinctly say, though I suppose this 
is his opinion. The ganglion cells, he says, generally send their 
processes into the fibrillar mass, and here they can sometimes be 
traced only for a short distance, sometimes he has seen them, 
even, penetrate the whole fibrillar mass of the ventral nerve- 
cord (»dans toute son epaisseur«). Whether he supposes a direct 
origin of the nerve-tubes in ganglion cells or an indirect one, I am 
not quite sure. In the head of Polygordius he describes two masses 
of ganglion cells in which »émerge un faisceau de fibrilles nerveuses 
formant un gros nerf qui constitue Taxe de chaque tentacule« (1. c. 
p. 263). P. 270 he says: »Beaucoup de prolongements de ces 
cellules pénétrent dans la masse fibrillaire et contribuent å la forma- 
tion du faisceau longitudinal; d'autres traversent verticalement la 
region fibrillaire. « Of the tentacular nerves of Protodrilus and Sacco- 
cirrus he says, however, that they take their origin »de la masse 
centrale fibro-ponctuée du cerveau.« The same he, also, says of the 
commissures. 
Vejdovsky, in his Monograph on the OUgochcetes (1884), gives 
us no distinct description of our subject though he mentions it rather 
circumstantially. The fibrillar »Punktsubstanz« he describes as con- 
sisting of slender nervous fibrillæ. Of the fibrillar mass of the ventral 
nerve-cord he says, for instance, that it »aus feinen, nur in derLangs- 
richtung verlaufenden und dicht neben und aneinander liegenden 
Nervenfibrillen besteht die bald einen gleichen kaum mehr als einen 
Bruchtheil eines Mikromillimeters erreichenden Durchmesser haben, 
bald, und dies in der grosseren Anzahl in der Mitte mit einer 
spindelformigen Anhaufung eines feinkornigen Plasmas versehen sind 
(Taf. VIII, fig. 2'). Weder eine besondere Membrann, noch ein 
Kern kommen an diesen, wohl den letzten nervosen Formelementen 
zum Vorschein; indem sie, wie wir spater unten erkennen werden, 
dem Zerfall einiger wenigen urspriinglichen Ganglienzellen ihre Ent- 
stehung verdauken. « 1) This description is written from observations 
on the living animal. Vejdovsky does not mention any interfibrillar 
substance like Hermann, and others, it is, therefore, very difficult 
to say whether he has seen the sheaths of the nerve-tubes, and 
described them as fibrillæ like most writers, or if he has really seen 
the nerve-tubes, but not observed their sheaths. I feel disposed to 
1) 1. c p. 91. 
