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VlALLANESs voluminous papers (1884, 1885, 1887) on the nervous 
system of Atheropods have not much interest for our present re- 
searches, .as he has paid no special attention to the minute structure 
of the nervous elements. Regarding the structure of the dotted 
substance, he only quotes the general opinions of other authors, 
and seems, especially, to believe in the descriptions and views 
afforded by Krieger and Vignal. The nerve-fihres (he distinguishes 
between three kinds: tuhes nerveux, fibres fibrilloides and fihres 
fiUformes) have no direct origin in ganglion cells, neither have 
the ganglion cells any direct combination with each other. Of 
the dotted substance (substance ponctuée) he says for instance (1. c. 
1884 p. 14): »C'est d'elle que tous les nerfs tirent leur origine, 
c'est dans elles que les prolongements des cellules ganglionnaires 
viennent tous se jeter. Ainsi les cellules ne peuvent communiquez 
entre elles, les nerfs ne peuvent communiquez avec ces mémes 
cellules que par Imtermediaire de la substance ponctuée. « 
BOHMIG (1884) has himself given the following summary of the 
results of his investigation of the dotted substance etc. of the Gastero- 
pods. »Die Markmasse wird von einem Punktsubstanzballen gebildet. 
Unter Punktsubstanz hat man ein inniges, filzahnliches Gewirr von 
Primitivfibrillen, aus welchem die Zellfortsatze gebildet werden, zu 
verstehen. Aus der Punktsubstanz gehen die Nerven durch eine 
parallele Anordnung der erst wirren Primitivfibrillen hervor. Durch 
eindringende Bindegewebssepten werden die Fibrillen zu secundaren 
Biindeln vereinigt. Eine directe Uebergang von Zellfortsatzen in die 
Nerven, also ohne vorherige Auflosung in der Punktsubstanz, kommt 
vor; und zwar fast bei allen Nerven. Jedoch ist diese Erscheinung 
selten« (1. c. p. 45). As will be seen, this view is somewhat similar 
to that of Solbrig; the nerve- fihres may have a direct origin as 
well as an indirect one. 
Packard (1884) makes, in my opinion, some very interesting 
statements regarding the structure of the brain af Aselliis commimis. 
As to the structure and importanee of the dotted substance, or 
»myeloid substance « as he calls it, he does not think himself in 
a position to say anything with certainty. He says of it (1. c. 
1884 p. 6): »This latter substance does not exist in the nervous 
system of the vertebrates, and just what its nature and function 
clearly are in the invertebrates has yet to be worked out.« »His 
own opinion from what little he has seen is, that the myeloid sub- 
stance is the result of the splitting up into a tangled mass of very 
fine fibrillæ of certain of the fibres thrown off from the mono-polar 
