398 S. J. HOLMES 



to the analysis of behavior, as contrasted with the method of 

 first analyzing behavior into its component factors, with the 

 view of later resolving these still further and perhaps finally 

 in terms of physical and chemical laws. The author considers 

 the latter method the more feasible. 



A detailed study was made by Kribs ^^ of the reactions of 

 yEolosoma to chemical stimuli of various kinds and degrees 

 of strength. Attention was paid to the variability of the re- 

 actions, the influence of previous stimuli, and the condition of 

 the organism. There is a final section devoted to a discussion 

 of the general bearing of the results. 



Positively phototactic Daphnias and Balanus nauplii, when 

 exposed to the light of a spectrum, were found by Loeb and 

 Maxwell ^^ to congregate most abundantly in the green, 

 as was found to be the case also with Chlamydomonas. 



A part of McClendon's paper " is devoted to a description of the 

 adaptations of two crustaceans, an Alpheus and a Trypton, which 

 show certain similarities, presumably due to their similarity of 

 habitat. The other part of the paper is devoted to an account of 

 the behavior of an anemone, Cradactis, which commonly lives 

 in crevices among the rocks. Light causes Cradactis to creep 

 away by movements of its foot, or by turning over and crawling 

 on its tentacles. The contraction of peculiar frond-like out- 

 growths of the tentacles at night and their expansion during 

 the day is attributed to their positive phototaxis. 



Mast " finds that a sudden increase of light intensity inhibits 

 the movements of Amoeba, but its activities are resumed after 

 continued exposure. Amoeba moves aw^ay from the light in a 

 fairly direct path, and its orientation is determined by the 

 inhibition of pseudopod formation on the more illuminated 

 parts. There is no evidence that the direction of light per se 

 has a directive effect on the movements of the animal. Blue 

 light is the most potent in inducing phototaxis, while violet, 

 green, yellow, and red have in general little effect. 



Moore ^^ holds that the righting movements of the starfish 

 are not determined by gravity, but by the " positive stereo- 

 tropism of the tube feet." Which arms are employed in righting 

 depends upon their size, any injury the arms may have received, 

 and any initial twist they may have. The starfish studied 



