IN HIGHER INVERTEBRATES 



57 



with painful sensations. Other Octopi manifested still greater 

 intelligence, for they pulled hermits out of their shells, taking care 

 not to touch the zoophytes, realizing apparently that these were 

 the stinging element. More remarkable than this is an observation 

 made by Madame Jeannette Power. This lady on one occasion 

 saw an Octopus, that held a stone by one of its arms, watching a 

 large bivalve (Pinna) of which the shell was beginning to open. 

 When this operation was complete the Octopus quickly inserted 



Fig. 1062. A Limpet (Patella vulgata) leaving its Scar at Ebb-tide 



the stone between the valves so as to prevent them from coming 

 together again, and then proceeded to make a meal of the helpless 

 bivalve. 



Some of the Gastropods possess a well-marked " homing 

 instinct ", a particularly good example of this being afforded by 

 the Common Limpet (Patella vulgata, fig. 1062). As elsewhere 

 described (see vol. ii, p. 197) this creature lives on a particular 

 spot, which in course of time becomes a more or less well- 

 marked " scar ", to which it can hold so firmly as to defy waves 

 and tide. From this home it wanders out to feed when un- 

 covered by the water, and also when well covered. From such 

 excursions, which may extend to a distance of several feet, it 

 later on returns to settle down again on the scar, the surface 



