CORA D. REEVES 



Fig. 2 



Perspective View of Aquarium and lamphouse with part of each cut away, to 

 show interior. 



AquariiDu and fond rclcnsp. 



1. Stimulus compartment: /' /" recess for stimulus plate. 



2. Discrimination Compartment. 



3. Retention Compartment. 



A, movable partition between 1 and 2 (the partition between 1 and 3 not in place). 



C, fixed partition. 



D, sliding door in A. 



EG, parts of the frame which surround the base of the lamphouse. 



IJ, slender food-bar in position for feeding the fish. 



A", position of electro magnet by which the food-bar may be held in horizontal 

 position. 



Light Apparatus. 



L, II. lamphouse. Below L, H, hooded air-inlet. 



M' . C', partition through lamphouse, an upward extension of C. 



A'^, Nernst lamp in one half of lamphouse, one in the other half partially shown. 



The glowers of these lamps are across the compartments and thus parallel with 

 the long axes of the cylindrical lenses shown at SL. They are at the principal foci 

 of these lenses: 



O, slit opening of variable width. 



P. sliding metal plates which form the slit. 



Q, frame which supports metal plates PP and in which they slide. 



RF. ray filter in its kit. 



SL. cylindrical lens. 



S, S. stimulus plates. 



W, indicates water level. 



