512 ALLIS. [Vot. XII. 
appear, as they do toward its anterior end, and the fibres of the 
bundle enter, in large part, with the fibres of the lateral bundles 
into the anterior end of the lobus. A very small bundle, how- 
ever, continues backward outside the brain membranes to the 
hind end of the lobus. There in all my series of sections but 
one it was lost. In that one series what seemed to be the nerve 
entered the base of the brain lateral to the anterior end of the 
recessus interolfactorius, that is, in Amaia, in front of the lamina 
terminalis, or sulcus olfactorius, and hence into the lobus olfac- 
torius and not into the fore-brain proper. This root of the 
olfactorius, or nerve if it be a separate nerve, is found in the 
adult in the same position as in the young, but in none of my 
specimens could I trace it into the brain or find where or how 
it ended proximally. It becomes delicate and disappears in the 
membranes of the brain, broken doubtless in preparation. Dis- 
tally it could be separated from the ventro-median bundle of the 
olfactorius further forward than was possible in sections of lar- 
vae, but it finally ran into that bundle, as it did in the young, 
and could not be separated from it. 
In 12 mm. larvae the large cells found in the ventro-median 
bundle of older larvae are collected into a compact mass lying 
on the ventral and median surface of the olfactorius at about 
the middle of its length. The mass has a well-defined limiting 
membrane, and forms a knob-like structure on the outer surface 
of the olfactorius, the nerve and mass much resembling in 
arrangement and general appearance the nervus oculomotorius 
and associated ciliary ganglion. The cells of the mass are 
exactly similar in appearance to those of the ciliary ganglion, 
and it may therefore be, as that ganglion is said to be in whole 
or in part, a sympathetic ganglion, possibly the sphenopalatinum 
of higher vertebrates, though I found no connection whatever 
between it and the nervus trigeminus. The main olfactorius, 
at this age, is often distinctly double at its base, that is, it arises 
by two roots, one of which, in sections, is lateral and dorsal and 
the other median and ventral. With the median of the two 
roots the nerve or bundle “n”’ of Pinkus is associated. In 
the adult the separation of the two roots is not distinct. In 
sagittal sections of the adult brain a triangular space is, how- 
