1054 The American Naturalist. [December, 
the center of the sense of sight and the sense of touch in the antenna, 
and, moreover is the seat of whatever intelligence the animal possesses. 
The direction of the forced motion toward the uninjured side indicates 
that the fibers from the ganglion cross to the opposite side in their 
course. This crossing must take place in the extreme anterior portion 
of the ventral cord. 
A part of the functions of the ventral cord are shown in the decap- 
itated trunk. As stated above the power of coordination of motions 
remains to a large extent, and the animal is able to right itself when 
overturned. The decapitated trunk is, moreover, very sensitive to 
various external stimuli. A light breath of air will often set it in 
motion, and if the hot wire be held within one eighth of an inch the 
heat is usually sufficient to cause quite violent movements. This 
extreme sensitiveness to heat is very marked in all cases. 
Ifnow the different portions of the cord be examined, it appears 
that it is practically the same in function along its whole length. Ifa 
decapitated trunk be cut in half, both portions show about the same 
egree of activity, and neither varies much from the whole trunk 
except that in these smaller portions death ensues more quickly. Either 
of the two halves when overturned makes very evident attempts to 
right itself, but usually does not succeed because it is too short. If 
each of these halves be again cut in half, each of these pieces can 
still be made to advance by means of stimulation. When placed on 
the back some slight movements are seen which soon cease, and the 
piece remains perfectly quiet until again stimulated. Further than 
this the sense of equilibrium cannot be traced. It requires the pres- 
ence of several segments in order to manifest itself. Whether, if the 
weakening effects of the shock and the extreme mutilation could be 
avoided, it would assert itself with the presence of a single ganglion 
cannot be definitely stated. It is, however, more probable that the 
coordination of more than one is necessary. The power of advancing 
when stimulated is still evident in a piece which possesses only three 
pairs of legs; a piece with two pairs of legs when stimulated makes 
movements, but apparently has not sufficient strength to advance. 
Portions of the trunk from the anterior and posterior part of the body 
appear about alike in these respects. Various other methods were 
employed in the examination of the cord, such as cutting or burning 
through the cord without severing the body, or destroying the super- 
esophageal ganglion without removing the head. They all lead to the 
same conclusions in regard to its functions. 
