218 
J. BEARD. 
From what is known about the development of all other motor 
nerves, we may expect that such is the case ; and I believe that 
sooner or later it will be shown that these fibres, which are the 
nerves to the muscles of the gill-clefts, do develop as direct 
outgrowths of cells in the brain like the anterior roots of 
spinal nerves. 
When one also considers that to those four groups of nerves 
distinguished by Gaskell there must be added a fifth ganglio- 
nated sensory element connected with the lateral sense organs, 
the exceedingly complicated nature of the problems presented 
by the cranial nerves of any Vertebrate higher than Amphi- 
oxus will be very evident. 
Resume or Results. 
The spinal ganglia of Vertebrates are formed as differentia- 
tions of the inner layers of the epiblast just outside the limits of 
the neural plate. As the result of the cutting out from the epi- 
blast of these ganglionic elements an appearance is presented by 
the epiblast which is left, to which Professor His gave the 
name of “ Zwischenstrang.” This has no share in the formation 
of the ganglia. “ The Zwisclienrinne ” of His has no existence, 
but certain portions of the cranial ganglia, called here neural 
ganglia, are developed from the epiblast before closure of the 
neural tube in exactly the same way as the spinal gan- 
glia. These portions of cranial ganglia are more or less 
homologous with spinal ganglia, possibly only with the sympa- 
thetic portion of the spinal ganglia Anlagen. After separa- 
tion from the epiblast the neural cranial ganglia and the 
spinal ganglia get carried up with the closing in of the neural 
tube, and come to lie between its lips, but are quite distinct 
from the central nervous system, and the line of boundary 
between the two can always be distinguished. After the 
closure of the epiblastic folds the Anlagen grow out of their 
position between the lips of neural tube, which then also 
closes. They grow downwards and to the sides of the neural 
tube, and acquire their first and only connection with it by the 
