26 ANIMAL INTELLIGENCE. 



Some evidence of intelligence seems to be displayed 

 by the razor-fish. For the animals dislike salt, so that 

 when this is sprinkled above their burrows in the sand, 

 they come to the surface and quit their habitations. But 

 if the animal is once seized when it comes to the surface 

 and afterwards allowed to retire into its burrow, no 

 amount of salt will force it again to come to the surface. 1 



With regard to snails, L. Agassiz writes : ' Quiconque 

 a eu 1'occasion d'observer les amours des limacons, ne 

 saurait mettre en doute la seduction deployee dans les 

 mouvements et les allures qui preparent et accomplissent 

 le double embrassement de ces hermaphrodites.' 2 



Again, Mr. Darwin's MS. quotes from Mr. W. White 3 

 a curious exhibition of intelligence in a snail, which does 

 not seem to have admitted of mal-observation. This 

 gentleman ' fixed a land-shell mouth uppermost in a 

 chink of rock ; in a short time the snail protruded itself 

 to its utmost length, and, attaching its foot vertically 

 above, tried to pull the shell out in a straight line. Not 

 succeeding, it rested for a few minutes and then stretched 

 out its body on the right side and pulled its utmost, but 

 failed. Besting again, it protruded its foot on the left 

 side, pulled with its full force, and freed the shell. This 

 exertion of force in three directions, which seems so 

 geometrically suitable, must have been intentional.' 



If it is objected that snail shells must frequently be 

 liable to be impeded by obstacles, and therefore that this 

 display of manoeuvring on the part of their occupants is to 

 be regarded as a reflex, I may remark that here again we 

 have one of those incessantly recurring cases where it is 

 difficult to draw the line between intelligence and non- 

 intelligence. For, granting that the action is to a certain 

 extent mechanical, we must still recognise that the 

 animal while executing it must have remembered each of 

 the two directions in which it had pulled ineffectually 

 before it began to pull in the third direction ; and it is 

 improbable that snail shells are so frequently caught in 

 positions from which a pull in only one direction wil] 



1 Bingley, loc. cit., vol. iii. p. 449. 



* De VEspece et de la Clause, &c., 1809, p. 106. 



9 A Londoner's Walk to Edinburgh, p. 155 (1856). 



