THE ORIGIN OF CHORDATES 
BY 
Dr. H. C. DELSMAN 
(Continued) 
Objections to their views. — The views of FüRBRINGER, 
based on his admirable investigations, have found a 
wide acceptance among zoologists. Yet, after having repea- 
tedly studied his work and that of FRORIEP and others, 
I am not convinced of the accuracy of the conclusions of 
both these authors; on the contrary, my doubts have 
increased each time so that now, after a careful study of 
the results of embryological work on this subject, [feel sure 
that both are wrong in several respects In the first place 
I must object to the view of FRORIEP, that the hypoglossus 
in Amniotes and Selachians has no connection with the 
vagus and the accessorius, or, casuquo, the vago-acces- 
sorius. If, with ÓEGENBAUR, we consider the vagus and its 
ganglion as a product of the fusion of four dorsal nerves 
and their ganglia, then, truly, the discovery of more or less 
vestigial ganglia to the hindmost roots of the hypoglossus 
necessarily leads to the conclusion that the hypoglossus- 
roots, after having lost their dorsal components and ganglia, 
secondarily have moved forward under the vago-accessor1us, 
which in its turn has lost its ventral roots—however strange 
such a displacement may look at first sight! If, however, with 
several later investigators, we assume that the vagus has 
arisen by the fusion of a lesser number of dorsal roots 
or even was originally a single dorsal nerve (HATSCHEK, 
1892, p. 157) which has “collected” the ventral parts of 
the dorsal roots (rami post- and praetrematici) of a number 
