206 RALPH EDWARD SHELDON 
is an evenly distributed area of small cells, forming the nucleus 
diffusus lobi lateralis of Goldstein, the substantia grisea lobi infe- 
rioris of Kappers, who divides it into a pars anterior and a pars 
posterior (figs. 78, 81, 84, 89, 103, 106, 117). The cells, as shown 
in Golgi preparations, possess elliptical or flask-shaped perikarya, 
with many finely spiny dendrites, resembling somewhat the undif- 
ferentiated cells of the area olfactoria lateralis. A number of the 
cells are shown in figs. 95 to 99. This undifferentiated area is 
evidently the primitive structure of the lateral lobes from which 
its nuclei have been gradually evolved. (Compare the condition 
of ganoids, according to Johnston.) 
Nucleus cerebellaris hypothalami. Appearing rostrally, at 
approximately the middle of the longitudinal extent of the lateral 
lobes, occurs a nucleus of large evenly distributed, scattered cells, 
the nucleus cerebellaris hypothalami of Goldstein (fig. 89). This 
extends caudally and laterally,’ gradually increasing in size until 
it occupies a large part of the transverse diameter of each lateral 
lobe (figs. 89, 103, 106, 117). It extends practially to the caudal 
part of each lobe, laterally. A small area, under high power, is 
shown in fig. 108. 
Corpus mammillare. The only remaining center of importance 
in the lobi laterales is the ganglion mammillare of Goldstein. 
Rostrally and dorsally it meets the tail of the nucleus rotundus; 
thence it extends caudally, always adjacent to the median wall 
of the caudal portion of each lobe (fig. 117), practically to the tip 
of the lobes. It is composed of very small, closely packed, evenly 
distributed cells of characteristic form (figs. 118, toluidin blue; 
119 to 121, Golgi). Where this nucleus comes into contact with 
the nucleus rotundus the two may be easily distinguished by the 
difference in the size and arrangement of the cells. 
In Weigert preparations the corpus mammnillare is easily dis- 
tinguished, owing to the large number of fine medullated fibers 
found in it, giving it a finely reticular appearance. 
A number of the cell groups here introduced will not be fur- 
ther considered but have been mentioned in order to give an 
accurate understanding of the relations of the different centers. 
