CHEMORECEPTION: LOCOMOTION AND ORIENTATION 



293 



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Square matrix of lamps — ~ 



Fresnel lenses : 



honeycomb collim 



ator* 



ceramic filter plates 



logic interface to 

 computer 



^square matrix of photocells on 

 10cm centers 



) 



KA 



Figure 15 Shark monitor tank II. (1) Water supply into any one of four peripheral 

 channels; the water enters the tank proper through a wall of ceramic filter material. (2) 

 Return of water overflowing through standing pipe (3). The light from the square matrix 

 of lamps suspended over the tank is collimated through a continuous layer of Fresnel 

 lenses resting on a flat black honeycomb of aluminum foil. From Kleerekoper et al. 

 (1969). 



Various computer programs allow analysis of many statistical relationships 

 among the variables and their behavior over time, not only in the monitor 

 tank as a whole but in restricted areas, which can be specified. 



Almost perfect laminar flow is obtained by admitting supply water into 

 the tank through the entire area of one of the tank walls (Figure 15.1), made 

 of ceramic filter plate and allowing it to exit through a similarly built op- 

 posite wall. This permits creation of discrete, controllable distributions of 

 chemical solutions in the water so that the locomotor behavior of a fish can 

 be analyzed as a function of the chemical condition prevailing in any area. 



The release of stimuli at discrete loci and the establishment of chemical 

 "trails" are made possible by 200 blunt hypodermic needles, embedded flush 

 in the floor of the tank, in a square matrix on 20-cm centers. These needles 

 are individually connected to a container through silastic tubing and can be 

 made to release, singly or in any desired combination, simultaneously or in 



