74. C. J. HERRICK AND G. E. COGHILL 
The spinal ganglion cells and the ventral horn cells have fully 
matured and the figure shows that both crossed and uncrossed 
reflex connections are possible at all levels of the spinal cord. 
Dorsal root fibers from the spinal ganglion neurones pervade the 
dorsal part of the white substance and the remainder of this 
_ layer is filled with various kinds of correlation fibers. Both the 
correlation neurones and those of the ventral horns send enor- 
dorsu. root. func. lateralis 
7 
Correlation’ 
neurone 
, 
Ventral horn neurone’ | t 
i 
fase. longifudinalis medialis / eee fl 
tr tecto-spinalis’ i 
tr. bulbo-spinalis’ 
; ‘ventral root 
tr spino- ator) H 
2----- 
r spino-cerebellaris 
Ir spino -fectalis 
Fig. 7 Diagram of the relations of some of the neurones of the spinal cord of 
larval Amblystoma. 
mous dendrites into all parts of the cross section of the white 
substance, some even crossing to the opposite side through the 
ventral commissure. 
From these relations it is evident that each peripheral motor 
neurone is under the direct physiological influence of every sort 
of nervous excitation which can be transmitted through the 
spinal cord. These excitations may come from the skin of its 
own or of very remote segments of the body through dorsal root 
