230 The Animal Mind 



with apex down is the same form as a triangle with apex 

 up, were demonstrating not their deficiency in form vision, 

 but their lack of an abstract idea of triangularity. It 

 may well be that such a perception of form in the abstract, 

 such an ability to analyze forms out of patterns, depends 

 upon the association between visual impressions and 

 movements like the hand movements of a human being; 

 few lower animals, of course, have the same kind of motor 

 experience of objects that man possesses. 



Special evidence of the comparative development of the 

 visual image in different genera of ants is suggested by 

 Wasmann to be furnished by the facts of mimicry. Certain 

 insects belonging to orders other than the Hymenoptera 

 inhabit ants' nests, and have in many cases become more 

 or less modified to resemble their hosts. Wasmann thinks 

 that these resemblances, which have been established on ac- 

 count of their protective value, are in insects living among 

 ants of well-developed visual powers, such as would deceive 

 especially the sense of sight, while in the "guests" of ants 

 whose vision is poor, the mimicry is adapted to produce 

 tactile illusions (762). 



§ 68. The Homing of Animals as Evidence of Image Vision 



The ability to find their way back to their dwelling place, 

 or to any other locality that has a vital significance for 

 them, is a power widely distributed among the most vari- 

 ous forms of animals. We have considered, in the chapter 

 on the Chemical Sense, the part which smell plays in this 

 process, and on page 100 we noted the fact that the percep- 

 tion of light direction is not wholly without influence in 

 some cases. The common human method of path-find- 

 ing is by the recognition of visual landmarks : when we 



