George L. Streeter 313 
DESCRIPTION OF PLATES. 
ACE 
Drawing showing the floor of the fourth ventricle of an adult human 
brain, enlarged twice. 
IPio Nuva) Ile 
The same, showing by interrupted cross lines the sections illustrated in 
Plates III and IV. The size and position of the various nuclei situated in 
the floor are indicated in outline on the right side. Where one lies beneath 
another the outline is dotted. Thus one recognizes that the hypoglossal 
nucleus is covered in greater part by the nucleus of the vagus and the nu- 
cleus intercalatus. Antero-laterally the vagus nucleus extends beneath the 
acustie field. The fasciculus solitarius is indicated by a lateral sub-division 
of the vago-glossopharyngeal area and is shaded slightly darker. The nu- 
cleus intercalatus and nucleus funiculi teretis, except for the striae medul- 
lares, lie superficial throughout their whole length. Together with the 
nucleus cochlearis is included the thin lamella-like nucleus situated in the 
tela choroidea inferior, overlapping the corpus restiforme. 
PrAtres Til anp IV. 
Frontal sections of the floor of the fourth ventricle, the numbers of which 
correspond to the interrupted cross-lines of Plate Il. These figures rep- 
resent sections enlarged twice as much as are the surface views on Plates 
I and II, i. e. four times natural size. Especial care has been taken to 
represent the furrows and ridges on the edge of the specimens, and the 
attachment of the tela choroidea inferior. 
