320 



CHEMICAL SENSES 



Figure 35 Locomotor track of Negaprion brevirostris under the 

 conditions of Fig. 33, but with a flow rate of 0.40 cm/s. After 

 Maynard (1976). 



CONCLUSIONS 



The overview of the "state of the art," presented here, reemphasizes the 

 need for quantitative documentation of the locomotor responses of sharks to 

 chemical and physical cues. The effects of behavioral interaction between 

 stimuli of different modalities has barely been considered in the literature, 

 although, in natural conditions, the animal is continuously bombarded by 

 stimuli, the values of which are frequently interdependent. Evidence for the 

 significance of interaction between chemical stimulation and water flow, as 

 well as chemical stimulation and light, has been presented for elasmobranchs 

 as well as teleosts. These interactions and their quantitative aspects deserve a 

 great deal more attention. The effects of multiple stimuli impinging simul- 

 taneously are virtually unknown and their study presents a challenge which 

 will have to be met if better insight into the responses of elasmobranchs (and 

 other animals) to environmental information is to be gained. 



REFERENCES 



Allis, E. P. 1919. The lips and nasal apertures in the gnathostome fishes. J. 

 Morphol. 32:145-197. 



Allison, A. C. 1953. The morphology of the olfactory system in the verte- 

 brates. Biol. Rev. 28:195-244. 



