OLFACTORY CENTERS IN TELEOSTS 209 
lobes. Thus it is shown that instead of a radix medialis and a 
radix lateralis there are nine distinct fiber bundlesrunning through- 
out the crura (figs. 123, 124,22, 23)? 
(1) Tractus olfactorius lateralis. The lateral tract, the trac- 
tus olfactorius lateralis, consists of three bundles, a pars lateralis, 
pars intermedia and pars medialis. These are composed entirely 
of centripetal fibers, arising largely from mitral cells of the lateral 
part of each bulb. A few fibers, however, arise from stellate 
cells more centrally placed (fig. 124). The tractus olfactorius 
lateralis, pars lateralis originates, chiefly in this way, from stel- 
late cells of the nucleus olfactorius anterior, a few of its fibers 
arising, however, from peripheral mitral cells (figs. 124, 137). 
The tractus olfactorius lateralis, pars intermedia is the largest 
and most important of the three. Part of its cells of origin lie 
in the nucleus olfactorius anterior, while the larger proportion 
are mitral cells from the lateral portion of the bulb rostrally and 
dorsally (fig. 6). One small bundle of fibers originates from the 
mesal part of the bulb, crossing dorsally to join the main tractus 
olfactorius lateralis, pars intermedia (fig. 6). The tractus olfac- 
torius lateralis, pars medialis is small but extends throughout 
almost the entire length of the bulb, arising partly from mitral 
cells and partly from stellate cells of the nucleus olfactorius 
anterior (figs. 6, 124). The fibers of all three portions of the 
tractus olfactorius lateralis pass through the crura (figs. 22, 23), 
and gradually spread out above the fissura endorhinalis (figs. 24, 
35) to end, without decussating, in the lateral olfactory area 
of the basal lobes (fig. 137), including all parts of the nucleus 
pyriformis and nucleus teniae. Fibers end throughout almost 
the entire length of the area, the fibers ending farthest rostrally 
arising from the tractus olfactorius lateralis, pars lateralis. All 
three tracts, however, give off fibers to all parts of the nucleus 
olfactorius lateralis, rostrally of the sulcus ypsiliformis. <A larger 
proportion of the fibers of all three bundles end farther caudally, 
however, in the nucleus pyriformis, beyond the sulcus ypsili- 
formis, and in the nucleus teniae. Golgi preparations show that 
in all cases the fibers bend abruptly dorsad usually branching 
at their termination. The termination of the lateral tract in the 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 22, NO. 3 
