390 S. J. HOLMES 



Orton (38, 39) has given .a detailed account of the feeding 

 mechanism and mode of feeding in Crepidula with observations 

 on the feeding activities of various other mollusks. 



Eubranchipus dadayi was found by Pearse (40) to be posi- 

 tively phototactic and in general positively geotactic in the 

 light and negatively so in the dark. After mating the females 

 resist seizure by the males and usually leave the surface and keep 

 quiet near the bottom. 



By means of several experiments on the starfish Plessner (41) 

 has brought out several differences between the functions of 

 the ocelli and the general photodermic sensitivity of the body. 

 The latter serves only as a means of reaction to variations in 

 the intensity of light. The ocelli do not enable the starfish to 

 see images nor to detect movement, but by their means the 

 starfish is able to direct its movements toward a slit of light 

 or a dark object. Removal of the ocelli involves destruction of 

 the power of locomotion to special regions of light or shade. 



H. Prizbram and Matula (42) have studied the functions of 

 the branches of an abnormal antenna of the spiny lobster Pali- 

 nurus. The antenna was furnished with three flagella. Two of 

 these conveyed sensor}^ stimuli but did not respond by move- 

 ment, but the third responded by movement to the application 

 of stimuli. 



K. Przibram (43) has pointed out certain analogies between 

 the random movements of some of the Protozoa and Brownian 

 movements. 



Sexton and Mathews (45) have described the food habits, 

 mating and general behavior of the young in Gammarus chev- 

 reuxi, a species inhabiting fresh and brackish waters around 

 Plymouth, England. 



Oregonia gracilis, like many other spider crabs, was found 

 by Stevens (46) to possess the curious habit of decking itself 

 with various foreign growths. Contrary to the results of Minkie- 

 wicz there was no tendency on the part of the crabs to select 

 materials that correspond to the prevailing color of the environ- 

 ment. Blinded crabs decorate themselves but they show no 

 reaction to light. Crabs which had been previously exposed to 

 white, yellow, blue, green or red light show a manifest tendency 

 to go toward the same kind of light when they are free to move 

 toward any one of these colors. 



