196 ANIMAL BEHAVIOUR 



shows control and selection. It may profit by experience, 

 even though it has no brain. 



The sea-anemone Antholoba, reticulata, described by 

 Burger, 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. Now 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 pedicellariaj 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, 

 and 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 



