364 ELIZABETH CAROLINE CROSBY 
into the dendrites of the hippocampal cells. This is the tractus 
tuberculo-corticalis (figs. 14, 15). Some fibers swing to the 
lateral side of the hippocampus; these may be cortico-tuber- 
cular fibers. Farther cephalad some olfacto-cortical fibers from 
the nucleus olfactorius anterior join this tract. 
Parolfacto-cortical tracts 
Tractus parolfacto-corticalis (figs. 16. 17). Fibers swing up- 
ward from the medial parolfactory area of the septal region to 
the dorso-medial cortex of the hippocampus, entering this latter 
mainly, at least, on the medial side. In view of the fact that 
the medial surface of the hippocampus is mainly concerned, 
as far as one can judge from the impregnations of its cells (see 
discussion of the hippocampal cortex), with the reception of im- 
pulses, it seems quite probable that these fibers are concerned 
chiefly in carrying impulses from the parolfactory area to 
the cortex, i.e., they are parolfacto-cortical fibers. Since the 
medial parolfactry nucleus receives fibers from the medial 
olfactory tract and short fibers from the tuberculum olfac- 
torium and since it is connected by way of the diagonal band of 
Broca with the lateral olfactory area and with the hypothala- 
mus by way of the medial forebrain bundle, this nucleus prob- 
ably serves as an olfacto-visceral correlation center and discharges 
the resultant of this correlation into the hippocampus by way 
of the parolfacto-cortical tract. just described. - 
Tractus cortico-parolfactorius (fig. 17). Accompanying the 
lateral border of the fornix longus (see the account of the fornix 
beyond) as it swings ventralward from the hippocampus, there 
are relatively numerous fibers which enter the more dorsal por- 
tion of the lateral parolfactory nucleus and, spreading out, dis- 
tribute to approximately all parts of this cell mass. Fibers can 
be traced from this nucleus passing out medialward and ventral- 
ward to join the medial forebrain bundle. Since the lateral 
side of the dorso-medial part of the hippocampus is concerned 
mainly with the discharge of nervous impulses (see the dis- 
cussion of the dorso-medial part of the hippocampal cortex), 
