174 
J. BEARD. 
cranial nerve, its ganglion, &c., as the glossopharyngeus. 
This is all the more in place, as Professor His, in his recent 
note of warning against the speculations of us unfortunate 
younger morphologists, does not hesitate to maintain as a 
fact the derivation of the auditory and olfactory organs 
from what he calls the “ ganglion Leiste,” which also gives 
origin to such ganglia as facial, glossopharyngeus, &c. I 
hope to show to Professor His’s satisfaction that this “ fact ” 
is as little a fact as his derivation of the spinal ganglia from 
the “ Zwischenstrang,” which is the continuation backwards 
of the “ ganglion Leiste ” of the head. 
A further complication is presented by the superaddition of 
the sense organs of the head (and their ganglia), excepting the 
eye, which all enter into relationships with those portions of 
the head ganglia which appear morphologically to correspond 
to the spinal ganglia. These complications will be more clearly 
explained in the course of the work. 
I have mentioned in a recent paper (No. 8) that the cranial 
ganglia are made up of more form elements than the 
spinal, and I observe that Professor Gegenbaur, without 
investigating the development, comes to the same conclusion 
(No. 21). 
The first traces of the cranial ganglia Anlagen are formed 
in exactly the same fashion as those of the spinal ganglia, and 
it is much easier, on account of their greater distinctness, to 
make out the earliest stages. In the embryo in which I 
described the first traces of the spinal ganglia such Anlagen 
can also be distinguished in the head region. As the meso- 
blast has not yet divided up into the body-somites, or so-called 
protovertebra?, the head-somites are also not formed, and so 
we are entitled to say generally, the traces of the posterior 
root ganglia of cranial and spinal nerves are formed very early 
and long before the closure of the neural plate. 
A figure through the head region of an embryo, as early as 
the one depicted in fig. 4, has been given by Professor Marshall 
in one of his papers (No. 48, fig. 1), but he gave no trace of 
any ganglionic formation, and, indeed, it is quite possible that 
