PREY-PREDATOR RECOGNITION 47 



or the "sympathetic caressing" tactile stimulation of commensal fish de- 

 scribed by Gohar (1948). 



Finally, I would like to suggest that the study of such problems is not 

 only of interest to those invertebrate physiologists studying coelenterates, 

 flatworms, annelids, or mollusks, but may be valuable also to the compara- 

 tive physiologist and the comparative ethologist. In spite of the obvious 

 dififerences in the physiological mechanisms concerned (Pantin, 1950), 

 there are striking analogies between the behavior patterns that I have 

 described and the innate behavior patterns studied by such workers as 

 Schnierla and Van der Kloot in insects and Tinbergen and Lorenz in 

 vertebrates. The latter author, in discussing the "innate behavior patterns" 

 that he has studied so carefully, points out (1950) that, while they are 

 superficially reflex-like in being triggered by specific stimulus situations, 

 they are actually indistinguishable from what von Hoist calls "automatic 

 rhythms." The threshold of a starving sea anemone to external stimuli 

 capable of initiating "phases" of feeding activity gradually decreases, 

 eventually to the point at which such phases begin in the apparent absence 

 of any special stimulus ; this seems strictly comparable to Lorenz' cases 

 where "Captive animals, deprived of the normal object or releasing situa- 

 tion . . . will persist in discharging the same sequences of movements at 

 a very inadequate substitute object or situation." 



It will be of the greatest interest if we can further analyze the different 

 integrating mechanisms presented to us by these animals, which eithei 

 have no central-nervous-system "black box," or whose "black box" is so 

 relatively accessible to investigation and so relatively simple. 



REFERENCES 



Batham, E. J., and C. F. A. Pantin, 1950a. Inherent activity in the sea-anemone, Me- 



tridium senile (L.). /. Exp. Biol. 27, 290-301. 

 Batham, E. J., and C. F. A. Pantin, 1950b. Phases of activity in the sea-anemone, 



Metridiion senile (L.) and their relation to external stimuli. /. Exp. Biol. 27, 377- 



399. 



Batham, E. J., and C. F. A. Pantin, 1954. Slow contraction and its relation to spon- 

 taneous activity in the sea-anemone Metridium senile (L.). /. Exp. Biol. 31, 84-103. 



Bullock, T. H., 1953. Predator recognition and escape responses of some intertidal 

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