OF DENISON UNIVERSITY. 
43 
hypoglossus (XII) springs, with a rather large number of fibres from the 
lateral margin of the pyramids. 
The increase in the size of the medulla from behind forward is 
accompanied by an increase in the amount of gray matter, and also an 
inter-reticulation of the gray and white matter. This reticulation is 
the forward extension of the formatio reticularis of the cord. The 
posterior cornua are divaricated cephalad, and between them are inter- 
polated accessory gray masses, the corpus cuneato gracile. The poste- 
rior part of the dorsal cornu increases in size, forming the tubcvcidum 
Rolandii. In the anterior (ventral) cornua the lateral giant cells dis- 
appear, but in the gray matter of the reticulum are very numerous me- 
dium and small cells. Only in the higher (cephalad) regions of the 
medulla do large multipolar cells (.08 mm ) reappear. 
In the caudal part of the medulla, near the pyramidal decussation, 
appear two groups of cells, the basal and lateral nuclei. Tne first is 
rather broader than the pyramids, dorsal to which it lies, and extends 
upward (cephalad) to about the middle of the medulla. The cells 
measure .016-. 02 mm., with nuclei. 008- 01 mm. in diameter, and have 
only obscure processes. This nucleus is divided into subordinate cell 
clusters by numerous fibres passing in all directions, which evidently 
have their origin here. The lateral portions of this nucleus are regu- 
larly perforated by the roots of the hypoglossus. The second group 
(nucleus lateralis), lies in the antero-lateral (ventro-lateral) portion of 
the medulla, extending a shorter distance cephalad. The cells are 
multipolar with angular outlines and are of median size and not closely 
packed. Another cell cluster, nuclus centralis., lies on either side of 
the ventricle and its cells are spindle shaped and longitudinally placed, 
measuring .024 mm. An additional cluster (hypoglossus nucleus), ex- 
tending a shorter distance caudad and lying ventral to the above, con- 
sists of multipolar cells .04 mm long, and retains its position near the 
ventricle, while the dorsal portion extends laterally toward the front 
A cell clustre in the corpus cuneato-gracile may receive the same name 
and anteriorly nucleus restifornie. Cephalad in the medulla, after the 
termination of the basal nucleus, angular cells, .04 mm. in diameter 
collect on either side of the raphe forming the nucleus of raphe. 
Cephalad from the nucleus lateralis, and distinctly separated from it, 
is the nucleus of the facialis, the cells of which are multipolar, with 
processes ascending to the root, and measure about .04 mm. 
The dorsal and lateral longitudinal bundles are indistinct, but a 
