COMPLEX RESPONSES 171 



suits. One set of experiments directed toward testing 

 this question may be described. 



Sagartia lucia occurs commonly between high and 

 low water marks and when exposed to the air it is re- 

 tracted. If exposed for a long time, a day or more, it 

 will dry up and eventually die from desiccation. Speci- 

 mens of this species that had been creeping actively on 

 a sheet of glass under water were exposed to air, where- 

 upon they retracted and dried slightly on their outer sur- 

 faces. When this resting state had been assumed, the 

 glass was set in an inclined position in a vessel of sea- 

 water and at such a level that the lower pedal edge of one 

 of these actinians was just in contact with the water, the 

 rest of the animal being exposed to the air. Although 

 it would have been easy for this particular actinian to 

 have crept down into the water, it remained inactive 

 and fixed to the spot for over three days while its mates 

 on the part of the glass that was under water crept about 

 freely. Similar trials on other individuals always 'gave 

 the same results ; the actinians remained fixed. Had they 

 crept into the water, it would have required further ex- 

 perimentation to have ascertained the reason for this, 

 but, as they regularly did not, the observations give no 

 grounds for the assumption of nervous activities of an 

 exceptional order. 



In examining the literature on the behavior of actin- 

 ians two tendencies are quite obvious. One emphasizes 

 the diffuse, non-centralized nature of actinian responses 

 and deals with the behavior of these animals in terms of 

 relatively simple reflexes and the like; the other brings 

 into prominence the unified action of these animals and 

 interprets their behavior from the standpoint of the 

 whole organism. It is by no means clear that these dif- 



