254 
The Ohio Naturalist. 
[Vol. VIII, No. 4, 
As to whether the placodal portions of the communis ganglia 
give rise to special visceral fibres only, or to both special and 
general visceral fibres there is less certainty. The facts on which 
we may hazard a conclusion are as follows: 
Every cranial nerve containing gustatory fibres comes from 
a ganglion which can be traced wholiy or in part to an epi 
branchial placode. The VII, the cranial ganglion supplying by 
far the largest number of gustatory fibres comes from the largest 
epibranchial placode. 
The X, the cranial ganglion supplying the largest general 
visceral component contains the largest neural crest element. 
The smallest general visceral component is apparently in the 
VII nerve and there is possibly a small neural crest element in 
the gerniculate ganglion. 
The IX nerve is most interesting in this connection. I am 
unable to find any neural crest cells in the communis ganglion of 
the IX nerve and Professor Herrick describes it as supplying 
taste buds throughout its whole area of distribution and makes 
no mention of its supplying general mucuos surfaces. 
If this is ti'ue we have a pure special visceral or gustatory 
nerve coming from a pure placodal ganglion in the case of the IX, 
and a very reasonable deduction from this is, that the placodes 
give rise to that portion of the communis ganglion which supplies 
special visceral or gustatory fibres, the portion supplying 
general visceral fibres coming from the neural crest. 
The latter is homologous then in origin with the general 
visceral ganglia of the cord, but differs from them in that it 
dissociates itself from the general cutaneous cranial ganglia and 
fuses with that derived from the placode. 
The general cutaneous ganglia of the cranial nerves are 
quite distinct and there is even less excuse for confusing the 
cutaneous and visceral ganglion in the embryo than there is in 
the adult. 
If the epibranchial placodes give rise to the gustatory por¬ 
tions of the communis ganglia, we must look on the gustatory 
nerves as comprising a special visceral system because they end 
in visceral centers in the brain, and not because of any similarity 
in origin of the general and special visceral ganglia or because of 
the method of distribution of the gustatory organs. 
The ganglia are in no immediate sense related to general 
visceral ganglia in mode of origin, and the gustatory organs arc 
highly specialized and may be mainly ectodermic in position so 
that I think the term special communis ought to be applied with 
central brain connections always in mind as the justification for 
the term and this seems to be generally done. 
This generalization in regard to the origin of the gustatory 
fibres is too far reaching to be rendered safe by a study of one 
