190"] Jennings. — Behavior of the Starfish. Ill 



resulting in the perception of objects, or at least in a reaction 

 toward objects as such. The recent interesting work of Cole 

 (1907) shows that something of this sort is found in many lower 

 animals. Certain of my observations on the starfish seemed to 

 indicate that something of the sort, may exist in this animal. But 

 the results of observations on this matter were so inconstant 

 and varied so much with different individuals, that their sig- 

 nificance is uncertain. I give some of the facts merely as suggest- 

 ing further work along this line. 



It was noticed that if the starfish were exposed to the light in 

 a flat ve&sel with low, opacjue sides (galvanized iron or the like), 

 they often did not behave in the same way as when similarly 

 exposed in a vessel with glass sides. In the latter case they 

 commonly move straight away from the source of light. In the 

 vessel with opaque sides, they frequently move instead toward 

 that side of the vessel that is nearest to them. This is not a mat- 

 ter of light and shade, for it occurs when the side toward which 

 the starfish moves is in the full light, and caMs no shadow in the 

 direction of the animal. These relations are illustrated in the 

 following experiment : 



Side by side were placed a galvanized iron pan 40 cm. long, 

 with sides 6 cm. high, and a large glass vessel of nearly the same 

 size. The vessels were placed in the direct sunlight, and in such 

 a way that the sides of the opaque vessel did not cast shadows 

 into the pan save on the proximal end, — the right and left sides 

 being parallel with the sun's rays. Now I placed one after an- 

 other seven starfish in the iron pan, and observed their move- 

 ments. They were placed in various parts of the pan, but always 

 in such a way that the shadow of the side next the sun did not 

 fall upon any part of the animals. Only one of these starfish 

 moved directly away from the source of light, in the direction of 

 the sun's rays. Three that were near the left side of the pan 

 nioved directly toward that side. Three others, that were near 

 that side of the pan next the sun (though not at all in the shadow 

 of that side), moved directl.y toward that side (hence toward 

 the source of light), and placed themselves in the shade. Now 

 these same seven starfish were transferred one after another to 

 the vessel with glass sides, some nearer one side, some another. 



