68 
Psyche 
[March 
Spider No. 
Fork-to-dorsum-stimulus No. 
1 
2 
3 
4 
5 
drop 8 in., 
drop 6 in., 
back in 3" 
shuttle shuttle back 1 
shuttle 
back in 10" 
2 
reach, then 
reach, then 
reach, then 
shuttle 
shuttle back 
shuttle, 
shuttle, 
shuttle, 
back in 5" 
back in 5" 
back in V 
3 
shake 
shake, then 
shuttle 
shuttle back 
shuttle 
shuttle back 
5 
shuttle, 
back in V 
shuttle 
shuttle back 
shuttle 
shuttle back 
Subsequent 
1 
Changes to 
reaching, continuing for three 
successive stimuli by 
fork 128. 
2 Alternate shuttle and back for eight further stimuli, with accom- 
panying spread or reach; later stimuli no shuttle, spread or 
reaching only, including final stimuli by fork 128. 
3 With one intercurrent exception (shift and shake) seven each alter- 
nate shuttle and shuttle back, no reach or spread, no diminution 
of reactivity. 
5 Uncomplicated shuttle and shuttle back for 22 more stimulations, 
last four to fork 128. Later occasion, this date, 34 responses: 
shuttling changing to reaching, to fork 256; then repeated 
shuttling to fork 128; then again shuttling changing to spread to 
fork 256; then further shuttling and back to fork 128. 
In 1935, and in the earlier observations of 1936, the fork 
was regularly approximated tip to spider’s dorsum, long 
axis of fork about 45° to vertical axis of orb, moved through 
a plane at right angles to the plane of the orb. It was noted 
that in minor asymmetries of stimulation therein arising, 
the spider uniformly shuttled in a direction away from that 
of the fork’s approach, though the movement might not 
begin till the fork seemed quite opposite the dorsum. In 
later observations, principally those of 7-18-36, effort was 
made at more control of this factor. The fork was held 
vertical, and moved in a plane parallel to the plane of the 
orb. The tip of the fork then approached the dorsum either 
by a lateral movement from right or left (designated L) or 
downward from above (designated A; location of nests 
made it impracticable to approach upward from below) . In 
such observations it is vital that no strand of the web be 
touched by the vibrating fork ; often no easy matter, as it is 
^‘Shuttle” denotes movement from normal station; “shuttle back” 
denotes return to normal station. 
