TuRNER, Mushroom Bodtes of the Crayfish. 355 
they are removed from the brain, we must conclude that the 
optic tracts homologize well. A comparison of the tracts found 
in the crayfish with those found by Kenyon (’96) in the bee 
illustrates this statement. 
Fibers Related to the Antennulary Nerve. The antennulary 
nerve of Caméarus has two prominent roots: the olfactory root 
arising from the olfactory lobe, and the deutocerebral root aris- 
ing from the brain (fig. 14). On entering the brain the fibers 
of the olfactory root diverge and pass to the olfactory lobe 
Gig. 14, OLT.) 
The deutocerebral root is related to the following intra- 
cerebral tracts. 
Antennulo-mesal Tract. This isa narrow non-decussating 
tract which passes from near the meson to the antennulary nerve. 
Major Antennulary Tract. ‘This, the broadest of the an- 
tennulary tracts, passes direct from the antennulary lobe to the 
anternulary nerve of the same side (fig. 14, JZ. Aut.). 
Antennulary Commissure. This commissure is situated near 
the opposite side of the brain from that on which the nerve 
enters (fig. 11, Anz.C.) 
Dorsal Antennulary Tract. This tract passes in a broad 
curve from the dorsal tract nidus to the antennulary nerve 
(fig. 15, D. Ant.) 
Minor Antennulary Tract. This is a small tract which 
passes, without decussating, from a nidus near the collar to the 
antennulary nerve (fig. 16, Jz. Ant.). 
Fibers Related to the Tegumentary Nerves. In connection 
with the tegumentary nerve it has been possible to demonstrate 
the existence of the following tracts. 
Major Tegumentary Tract. This is is a broad tract which 
passes direct from the tegumentary lobe to the tegumen.ary 
nerve (fig. 12, M7. 7.). 
Mesal tegumentary Tract. This is is a small tract which 
arises from anidus situated near the meson on the opposite 
side of the brain from that on which the tegumentary nerve 
root is situated. It passes along parallel to the meson until 
