xvi JOURNAL OF COMPARATIVE NEUROLOGY. 
broad morphological plan of the central nervous system. Compare the 
paper by JoHNSTON on the Functional Divisions of the Central Nervous 
System in the issue of this Journal for March, 1902. 
This failure accounts for the error on p. 408 in homologizing the 
fasciculus solitarius of the oblongata with the oval bundle and hence 
with the column of BurDAcH of the spinal cord. The components of 
the peripheral nerves are ina later section correctly given and made 
excellent use of, and a recognition of the fact that the primary and sec- 
ondary centers of these components within the brain (especially those 
of the sensory roots) are likewise clearly differentiated would have shed 
much additional light on the problems of the functional divisions or 
zones of the metencephalon. 
The differentiation of the ventral plate into somatic and visceral 
series of nuclei is clearly presented (after His) and the visceral (lateral) 
series is associated with the branchial muscles and their derivatives. 
This is the traditional view and the one which the reviewer has 
adopted in his own studies as his working hypothesis; nevertheless it 
should be recognized that it is not wholly supported by the published 
facts, especially in the most recent literature, notably the papers of 
EDGEWORTH. ‘The whole problem of the embryology of the cranial 
mesoderm of vertebrates requires a renewed investigation and thorough 
critical analysis. 
In discussing the histogenesis of the ventral spinal roots, these 
fibers are described according to the now current theories as arising 
wholly from the neuroblasts of the ventral zones of the spinal cord. In 
view of the constantly recurring evidence of the end-to-end concatena- 
tion of cells in the formation of peripheral nerves, some mention should 
have been made of the ‘‘cellular nerve” of the embryo, even though the 
hypothesis that it participates in the formation of the definitive nerve 
fiber were rejected. 
On page 433, line 14, is an obvious misprint. The word ventral 
should be inserted before the word motor. 
The excellent discussion of the components of the peripheral 
nerves I would criticise in only one point; viz. the attempt to rank the 
olfactory nerve and organ as a member of the acustico-lateralis system. 
This very doubtful homology seems to be a relic of the errors of 
BLAUE, who endeavored to show that the ‘‘olfactory buds” of some 
fishes represent organs of the lateral line system which had wandered 
into the olfactory fossa and there differentiated. The futility of this 
argument was made clear on embryological grounds by MAnprRID- 
Moreno in 1886 and later by myself in 1899 (this Journal, Vol. IX, p. 
