STIMULI PRODUCED BY LIGHT AND BY CONTACT 
WITH SOLID WALLS AS FACTORS IN 
THE BEHAVIOR OF OPHIUROIDS^ 
R. P. COWLES 
Associate in Biology, Johns Hopkins University 
THIRTEEN FIGURES. 
The work of Preyer (1886-1887) on the reactions of echino- 
derms, in which he ascribed intelHgence to these lowly creatures 
and saw in their behavior a true ''will/' has stimulated many to 
study the behavior of starfish, ophiuroids and sea-urchins While 
all investigators since his time undoubtedly recognize the excel- 
lence of Preyer's observations and experiments, none have had 
the courage to endow echinoderms with intelligent action Some, 
such as Romanes and Ewart (1881), deny the existence of any 
psychic quality in these animals; others, such as Loeb (1900), 
Glaser (1907) and Jennings (1907), who have repeated some of 
Preyer's experiments see no intelligence indicated, while such as 
von Uexktill (1905), and Bohn (1908), and probably some of the 
above-mentioned workers also, will neither deny nor affirm its 
existence, although their experiments do not lead them to believe 
that echinoderms possess intelligence. Observation and experi- 
ment up to the present time do not confirm Preyer's contention 
and we have no cases indicating associative memory among the 
echinoderms, yet Jennings (1907), Bohn (1908), and Cole (1910), 
have shown that starfishes form habits. 
^ It gives me pleasure to thank the Carnegie Institution of Washington for the 
privilege of working in their marine biological laboratory. I also wish to express 
my appreciation of the courtesy and aid extended to me by Dr. Alfred G. Mayer, 
the director of the laboratory. 
