212 
J. BEARD. 
We have hardly begun to get any idea of the more primitive 
structures from which these two regions are derived. 
I have previously with Froriep, much to the disapproval of 
Gegenbaur, His, Dohrn, and Eisig (No. 15), sharply contrasted 
the cranial and spinal nerves and ganglia, and declared my 
conviction (No. 6) that it is a very doubtful question 
whether the two sets of organs ever had the same primitive 
characters. The development of the branchial sense organs 
and ganglia, in connection with the cranial ganglia, was my 
main consideration for saying this. And the same considera- 
tions appeared to Froriep (independently) to add strength to this 
conclusion at which he had arrived some years ago (No. 16). 
The question arises, How is the position altered by the 
researches I now record ? 
Eisig (No. 15, p. 542) had, perhaps rightly, urged against 
my views that it was not impossible that the spinal ganglia of 
Vertebrates represent the “ Seitenorganen ganglia ” of Capi- 
tellidse. Without devoting here the time which a thorough 
examination of Dr. Eisig’s comparisons entails, I cannot omit 
a partial discussion of this point. The exact weighing of the 
pros and contras of Dr. Eisig’s views must be left over for 
another publication, in which we must examine more closely 
the lateral sense organs of Vertebrates. 
I quote the following passage from Eisig’s great work 1 (No. 15, 
p. 542), in spite of its length, because it touches upon the pro- 
posed homology between the spinal and cranial ganglia on the 
one hand, and the parapodial ganglia of Annelids on the other. 
This homology, as I previously mentioned, was suggested by 
Kleinenberg (No. 41, p. 220), and in a strict morphological 
sense I think, as the result of my researches, it can be 
accepted. 
The passage runs thus (p. 542) : “ Es muss dagegen speciell 
der Punkt von mir erortert werden auf den sich Beard zum 
Behufe der Perhorrescirrung der Homologie von Gehirn uud 
Spinalnerven sti'itzt: namlich, die Thatsache, dass die Spinal- 
' I take this opportunity of expressing my gratitude to Dr. Eisig for the 
generous gift of a copy of his immense monograph. 
