372 The American Naturalist. ` [May, 
branches in the central cerebrum, and, after all the methods 
employed by me, I am compelled to say that I have been able 
to do little better. In one preparation by my formalin-hema- 
toxylin method there seems to be evidence of such branches ; 
but I have found no such evidence in bichromate of silver 
preparations. Finally, there are several small tracts below the 
last that terminate in the adjacent region of the central portion 
of the brain, and in the neighborhood of the terminations of 
the antero-posterior optic tract. 
The situation of the cells of origin of these tracts has not. 
been definitely determined, but some of them no doubt may be 
found in the neighboring posterior mass of cells (5 and 6). 
Two other tracts of fibres leave the inner fibrillar body. 
From the inner or concave surface of this there issue a large 
number of fibers that appear to be gathered up into two 
bundles. One of these passes forward as the anterior optic tract 
and terminates in the optic body (a, 0, t; op. b), a small oval 
mass of fibrillar substance just above the antennal lobe. The 
other passes upward as the postero-superior optic tract. It joins 
the antero-superior tract for a short distance, and then passes 
behind the stalks and apparently into the calices of the mush- 
room bodies. 
To this description and the one I gave in my former paper 
one might object, basing the objection upon the course and 
peculiarities of the fibers of the antero-superior tract, that 
since there is a tract of fibers connecting the inter-lenticular 
space of the second fibrillar body with the calices of the mush- . 
room bodies, one would expect to find this posterior tract 
making similar connections with the inner body. The point 
was a difficult one to decide, and caused me an expenditure of 
considerable time in coming to a conclusion ; but the evidence 
of my sections, both those by the formalin-copper-hematoxylin 
and those by the bichromate of silver, especially the latter, 
method, appears to be in favor of the description that I have 
given. 
Considering now the denser mass of the fibrillar bodies it 
may be said that in sections treated by the formalin-copper- 
hematoxylin method one may find evidence of fibers passing 
