OF DENISON UNIVERSITY. 
6i 
and the entire higher portions, afford opportunity to trace the connec- 
tions of the structures already described with the cerebral ganglia. 
Nuclei and tracts of the higher portion of the medulla and crural 
reg[ion, as seen in hor izontal sections. 
The bladder cells of the dorsal root of the trigeminus. These remark- 
able cells have already been referred fo. They seem to have been first 
recognized by Stilling, who regarded them as forming an accessory 
nucleus of the fourth nerve, in whose tract they nearly lie. Stieda 
(Zeitschrift f. wiss. Zoologie, Band XX,) falls into a worse error, re- 
garding these cells as the true nucleus of the fourth, and failing to 
discover the tract extending from the root cephalad, {^Loc cit. Plate 
XX, Fig, 44.) Stieda’s drawing is exceedingly conventional, so far as 
concerns cells and nuclei. 
Meynert (Striker’s Histology, Am. Ed., p. 705,) describes the 
cells in question as follows : 
“The cells from which spring the above mentioned roots of the 
fifth pair, differ strikingly, in regard to their shape, from the cells in 
the common nucleus of the oculo-motor and trochlearis. The former 
are inflated, bladder like, and furnished with but few and slender pro- 
cesses, which project abruptly from the cells like a straw from a soap 
bubble. The latter are large, like the former, but slender, and rich in 
processes whose calibre passes by gradual transition into that of the 
cells. The former resemble the cells of the spinal ganglia, the latter 
those of the anterior cornua of the spinal cord.” 
“ Even within the limits of the upper corpora bigemina, tbe cen- 
tral tubular gray matter encloses the nuclei which give rise to the motor 
nerve roots referred to (oculo motor, etc.), which lie more or less near 
the median line ; also a laterally disposed sensory nerve tract, the roots 
of the fifth cranial nerve. The fibres composing these roots originate 
at the outermost border of the gray matter which surrounds the aque- 
duct of Sylvius in small collections of large bladder-shaped cells 60 
micr. in length and 45-50 micr. in breadth.” 
In Arctornys the disparity in size between the cells of the nuclei 
of the fourth nerve and these bladder cells forbids comparison, other- 
wise the remarks quoted apply substantially. The deduction which 
Meynert attempts to draw regarding the relative position of sensory 
and motor nuclei in the medulla seems forced in this case, being based 
on the pure assumption that these cells are sensory, while the differ- 
