WHAT THE FISHES SEE 



eyes to secure impressions which the other sensations 

 cannot afford. 



This condition is associated with not less surprising 

 habits, in which we observe a connection between 

 optical sensations and the phenomena of memory. 

 Memory is primarily a matter of vision ; this is made 

 clear, as it were in a nutshell, in this little fish. It runs 

 readily to cover and takes shelter. It chooses a lair, 

 settles in it, makes a house of it, and seems to consider it 

 as its personal property. One of the basilisks I ex- 

 amined had made its home in the empty shell of a Pinna, 

 a large bivalve mollusc ; it fitted its body into the interior 

 of the shell, and put out its forepart through the gap 

 left between the lips. Using the gap as a window it 

 surveyed the neighbourhood. Its keen eyes, always on 

 the watch, turned in all directions, and the turnings of 

 the eyes were accentuated by movements of the head. 

 If doubtful creatures swam up, it either retired and hid 

 itself completely, or came out to meet the enemy and 

 put him to flight. The course was decided by the size 

 and presumed strength of the intruder. Sometimes, for 

 no apparent reason, it left its shelter, took a stroll 

 round the tank, then went straight to its place without 

 any apparent hesitation, guided by a precise topo- 

 graphical memory. Then it took up its position again, 

 entered the shell completely, turned round and finally 

 put out its head. If, in the course of its stroll, it met 

 one of its fellows, they both stopped, turned round 

 as if to recognize one another, then separated, each 

 going to its house, never making a mistake. It behaved 

 exactly like an intelligent little being, capable of man- 

 aging its own affairs quite well. As I watched it I 

 could not help thinking of the little land animals, 

 rodents or insectivores, their earths, holes, and hiding- 

 places. There was a real resemblance in almost every 

 respect. This blenny went about like a mouse. 



But when we come to results, this comparison, how- 

 ever justified it may be as regards the creature itself, 

 254 



