BEHAVIOR AND COLOR CHANGES OF TREE FROGS 75 



and H. arborea show a very marked similarity, as in other 

 points already referred to. 



Still other experiments were made but they add nothing 

 essential to those already described and need not cumber the 

 pages further. Compared with the accounts given by others 

 (vide supra), these may seem somewhat inconclusive; and but 

 for those relating to H. versicolor they would be so to the writer. 

 However, they are what they are, — facts to be reckoned with; 

 and as such are submitted for the consideration of any who 

 may be concerned with them. It may be worth while to merely 

 mention the observation of Meyer, cited by Biedermann (op. 

 cit., p. 489), to the effect that certain frogs (H. temporaria) 

 are more responsive in reactions to light during fall and winter 

 than in spring. ' Wenigstens bleiben in dieser Jahrzeit die 

 Thiere haufig im Licht dunkel, im Finstern hell." I cannot 

 believe, however, this can be of importance so far as the general 

 facts are concerned. 



Psychology of Behavior. It is no part of my present purpose 

 to enter upon a discussion of the intricacies of this feature of 

 behavior, but merely to suggest a very few points in connection 

 with certain aspects which have been submitted in earlier sec- 

 tions of the paper. Attention has already been directed to the 

 fact that frogs must be regarded as having small claims to 

 intelligence, and after one has had various species under obser- 

 vation for some time this verdict is not likely to be greatly 

 modified. While it is true that frogs have succeeded about as 

 well as the average of their class, and indeed better than most, 

 if one may judge from the number of either species or individuals, 

 still this has come about more by virtue of the peculiar instincts 

 and habits than by the degree of intelligence which has been 

 involved. However, one must not lose sight of such facts as 

 are clearly indicative of intelligence. Both by observation and 

 experiment it has been shown over and over again that frogs 

 are capable of learning, they have memory, they profit by 

 experience, etc. (cf. Yerkes, Instincts, Habits and Reactions 

 of Frogs. Harv. Psy. Stud., vol. I, 1903; Holmes, Biology of 

 the Frog, Chap. XIX, 1907). 



But, as already intimated, it is not my purpose to consider 

 this aspect of the problem. I have been concerned in observing 

 the very apparent association of emotional, and other neuro- 



