298 CHEMICAL SENSES 



responsible for serial correlation may be responsive to sensory information, 

 and hence to external stimuli. This assumption is supported by the fact that 

 water flow affects the strength of the serial correlation, a fact which will be 

 referred to again later. The degree of serial correlation differs among the 17 

 variables, which means that the strengths of the feedback mechanisms con- 

 trolling these variables are dissimilar. By comparing residual ratios and 

 means, it was established that some locomotor variables are subject to strong 

 feedback control and may therefore be considered rigid while others are 

 weakly controlled by feedback. It was hypothesized that the latter are there- 

 fore more readily modulated when the animal responds to the environmental 

 stimuli that provide directional cues for locomotion. 



It is notable that among the most weakly controlled variables are those 

 related to turning behavior: step length and mean turn size. When the vari- 

 ables are ranked by the strength of the feedback that controls them, the rank 

 order is rather consistent among the animals tested, in spite of great dif- 

 ferences in the absolute strengths of the serial correlations. The stability of 

 the ranking as well as other statistical properties strongly suggest the exist- 

 ence in elasmobranchs of a relatively rigid locomotor control mechanism. 

 Gerald et al. (in press) greatly extended the scope of the analysis of Gingly- 

 mosforaa's locomotion by describing the structure of the internal time de- 

 pendency within each of the locomotor time series and by constructing a 

 model of lesser dimensionality and internal dependency. Another feature of 

 that research, closely tied in with the above, will be referred to later in 

 discussing locomotor forecasting techniques. 



For the quantitative aspects of this and the previous study the interested 

 reader is referred to the original communications (Matis, Kleerekoper, and 

 Gruber 1975; Gerald, Matis, and Kleerekoper, in press). A comparative 

 study, in progress, of the above properties of locomotor variables in an 

 elasmobranch and in a representative teleost (goldfish) may shed light on 

 evolutionary aspects of locomotor control in fishes. 



LOCOMOTOR RESPONSES TO CHEMICAL STIMULATION 

 General responses 



In Scyliorhinus, stimulation with the odor of a conspecific in one of the 16 

 compartments of monitor I did not affect the relative frequency of move- 

 ments between compartments but did have a sustained effect (90 min) on 

 the distribution of "jumps" (number of compartments bypassed between 

 egression and ingression) as well as the relative participation of right and left 

 turns in this behavior as shown in Figures 20 and 21 (Kleerekoper 1967a, b). 

 In other words the frequency distribution of turn sizes as well as the role of 

 handedness in locomotion were affected. That the quality of the olfactory 

 stimulus does not affect the mode of the response mechanism appears from 

 the results obtained when Mustelus was stimulated not with food odor but 

 with the odor of Anemonia sulcata, a noxious organism. The compartment 

 releasing the odor substance as well as five of the neighboring compartments 



