PLATE 14 
Figs. 3 and 4. Other views of cage and recording apparatus shown in 
plate 13. 
ABBREVIATIONS 
blk.—adjustable block. 
b. p.—binding post through which the levers are connected with one pole 
of the battery. 
fl. sup —metal support attached to under side of floor and resting on slender 
pin driven into side of lever bar (p. br., pl. 13). 
lr. sup.—metal support for fulerum of lever. 
tr.—truss-like frame attached to floor to prevent tipping of latter. 
up.—upright posts which support the wire sides and top of the cage inde- 
pendent of floor. 
[130] 
