196 ANIMAL BEHAVIOUR 



shows control and selection. It may profit by experience, 

 even though it has no brain. 



The sea-anemone Antholoha reticulata, described by 

 Biirger, usually lives on the back of a crab. If it be re- 

 moved it fixes itself to the stony floor of the sea and spreads 

 its tentacles, biding its time. After four or five days it 

 frees itself and turns upside down. ]^ow if the upturned 

 base of the sea-anemone be touched by a crab's leg, it lays 

 hold, folding itself about the limb. " It now, in the course 

 of several hours, climbs up the crab's leg to its back, where 

 it establishes itself. The sea-anemone thus by its own activ- 

 ity attains the extraordinary situation where it is usually 

 found. The whole train of action is like that shown in the 

 complicated and adaptive instincts of higher animals " 

 (Jennings, p. 197). 



As the type-case of what we propose to call simply organis- 

 mal behaviour (or perhaps sensori-motor behaviour), we take 

 the attack which the brainless, ganglionless starfish makes 

 on the brainless, ganglionless sea-urchin (see Prouho, 1890). 

 The starfish lays an arm upon the spinose surface of the 

 sea-urchin and grips with its suctorial tube-feet. The sea- 

 urchin responds by biting with its numerous snapping organs 

 or pedicellarise which close on the tube-feet. The starfish 

 then draws away an arm, wrenching off the pedicellarise. 

 It repeats the process with the same or another arm until the 

 sea-urchin is cleared of its weapons. The starfish then pro- 

 trudes a portion of its highly elastic stomach over its victim, 

 apd the business is .over. Now some of the items in the pro- 

 cedure are probably purely reflex, such as the attachment 

 of the tube-feet, but the point is that the starfish exhibits a 

 chain of actions, certainly not in the line of least resistance, 

 which are mutually adjusted or correlated in such a way 



