BEHAVIOR OF VERTEBRATES 411 



brightness vision, questions concerning the color sense, adapta- 

 tion of skin to the water ground, range of vision, monocular and 

 binocular vision, position and movements of the eyes, and com- 

 pensatory changes of the eyes in relation to equilibration. The 

 object of the article as stated by the author is first to give a 

 reliable account of the knowledge gained in the last ten years 

 of the vision of fishes and second to awaken and stimulate in- 

 terest in the many biological questions that still await solution. 



TROPISMS AND ORIENTATION STUDIES 



Observers have differed as to which end of Amphioxus is in 

 advance during swimming. While working at the Bermuda 

 Station Arey (1) had an opportunity to observe the swimming 

 habits of a West Indian lancelet. He says that while Amphioxus 

 can swim backward for short distances its normal orientation is 

 with the anterior end in advance. Kanda (17) discusses geo- 

 tropisms in animals with the different explanatory theories of 

 the phenomena. He then attempts to connect the observed 

 behavior in many forms with the statolith organs. Brun (4) 

 gives a theoretical discussion of the orientation problem in gen- 

 eral for all animals but the discussion is based upon some experi- 

 mental work with ants. 



Our common minnows usually keep in shallow water near 

 the shore line and follow the tide in its movements. This be- 

 havior aids the fish in the escape from its enemies and the securing 

 of food. Mast (18) studied the actions of Fundulus when trapped 

 in pools which fill shallow depressions in the sand. He found 

 that ordinarily their movements were regulated in some way by 

 the ebbing and flowing of the tide as the behavior was quite 

 different at different times of tide. The fish flop out of the 

 pools and then with successive flops travel in a fairly direct 

 course to the sea. No matter what the axial direction of the fish 

 is as it falls the next flop will carry it on its course. The regu- 

 latory mechanism is uncertain. The author thinks that it 

 cannot be vision or the slope of the land. 



INSTINCT 



A most interesting note on the maternal instinct of monkeys 

 is given us by Yerkes (39). Gertie, a Rhesus monkey, for five 

 weeks carried about with her the vanishing remains of a still 



