2/6 CHAS. W. HARGITT. 



their behavior was closely watched after the specimens had be- 

 come adjusted to their new habitat. In this connection should 

 be mentioned the fact, to be discussed later, that some specimens 

 were much less prompt in burrowing, a few remaining more or 

 less indifferently upon the surface of the sand and showing but 

 slight attempts to bury themselves. 



It only required a few observations to determine beyond any 

 doubt that only in light of low intensity, such as twilight, or in 

 the aquarium under the rather dim light of an incandescent lamp at 

 some distance, did the specimens protrude their oral portions and 

 tentacles and show any degree of activity. To further demon- 

 strate that these seemingly nocturnal activities were not merely 

 a periodic response made at more or less definite intervals, the 

 following experiment was made. A tall glass jar, some twenty 

 inches in depth, the lower third of which was filled with sand, in 

 which had been placed several anemones some two days pre- 

 vious, was so placed on a laboratory table that it was freely ex- 

 posed to the diffused light of the room. Over the jar was 

 placed about mid forenoon, when the creatures were securely 

 withdrawn in the burrows, a blackened chamber or dark hood, 

 so arranged as to exclude more or less perfectly the light. Re- 

 moving the hood at the end of an hour it was found that the 

 creatures were quite extended as at night. And it was soon evi- 

 dent, that with the removal of the hood and the admission of 

 light, they were at once aware of the change and promptly began 

 to show signs of irritation, which ended within five minutes in 

 every specimen having retracted into its tube. To make certain 

 that the response had not been induced by some mechanical 

 stimulus, such as the tremor of passing steps, or an accidental 

 disturbance of the table or the water in the jar, the experiment 

 was repeated within a half hour and under conditions which 

 made it possible to observe the phases of the response. 



Within fifteen minutes after the chamber had been placed over 

 the jar it became quite evident that the change had been recognized 

 by the specimens. This was shown first by the extension of the 

 tentacles, and next by a slow protrusion of the oral region by 

 degrees, till within about half an hour the body was extended 

 an inch beyond the surface, as before. Again removing the 



