Charles R. Essick 129 
tongue-like process are well iliustrated. His figure 728 has almost the 
same level as Fig. 5, and here he has called it “pons (Varoli).” This 
latter is very natural when we consider that a little farther front the 
ponto-bulbar body is actually fused with the pons. 
In the tongue-like projection the cells occupy a central position, being 
surrounded on all sides by the fiber bundles which may then be regarded 
as forming a capsule; Figs. 9, 10, and 11 show this very well. Single 
fibers may be traced for some distance in a section showing that here in 
the dorsal portion the fibers take the same direction as the body that is 
toward the median line. These fiber strands run along the border of the 
nucleus and converge as they turn around to gain the lateral side of the 
restiform body forming a bundle which is gathered together in wisp-like 
fashion. The efferent fibers from the abducens, facial, and other nuclei 
have this same confluence into a root bundle. Toward the median end 
of this projection appears a rather large bundle cut transversely which 
gives off collaterals to the nuclear material in a very irregular manner. 
The above description apphes to adult material, but I have also had 
the opportunity of examining a series of the new-born babe, the one 
which was prepared by Dr. John Hewetson and belongs to the col- 
lection of this laboratory. In this series the ponto-bulbar body could be 
distinctly made out, and in its relations to the surrounding structures 
showed the same features as described in the adult. However none of 
its fibers are as yet myelinated, the non-myelinization made it particularly 
easy to identify it in the region of the cochlear nerve, ventral cochlear 
nucleus, and trapezoid body, all of which have at this age acquired their 
myeline sheaths. Further caudally where it hes against the side of the 
restiform body it comes into contact with the cerebello-olivary fibers. 
Although these unmyelinated fibers fuse with the ponto-bulbar body, the 
closely arranged ganglion cells of the latter are easily distinguished from 
the coarse nerve fibers. The pons with which this body fuses cephalically 
also contains no myelinated fibers. It may also be added that it is 
present in the early stages of both human and pig embryos. It can be 
seen in the reconstructions of this region in a 50 mm. human embryo 
which are about to be published by Dr. Streeter, and it was also noted 
by him in dissections of pig embryos. 
8G. L. Streeter: Development of the Membranous Labyrinth and the Ac- 
coustic and Facial Nerves in the Human Embryo. Amer. Jour. of Anat., Vol. 
Wale ios alas 
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