388 S. J. HOLMES 



remains expanded in the light and contracted in the dark, and 

 shows no diurnal or tidal rhythms independently of the changes 

 of the stimuli directly affecting it. 



In the course of an investigation of the alleged color sense 

 of the lower animals Hess (24) has experimented on various 

 fishes, the larvae of Culex, and the anemones Cerianthus and 

 Bnnodes. The general results are confirmatory of his conten- 

 tion that the lower animals are color blind, i.e., they are affected 

 only by the intensity and direction of the light rays. 



In the course of a general account of the biology of Asellus 

 aquativus Kaulbersz (26) describes many features of the behavior 

 of this isopod, and especially its reaction to chemical, photic 

 and tactile stimuli. Observations were also made on the reac- 

 tions of Gammarus and Niphargus. 



Kchschkowsky (27) has studied the effect of the constant elec- 

 tric current on various cestodes, nemerteans and annelids. Most 

 forms reacted by a contraction of the longitudinal muscles when 

 the anode was placed at the head end and the cathode near the 

 tail. 



Following a description of the histology of the sensory epi- 

 thelium of Microstoma caudatum, Kepner and Taliaferro (28) 

 have given an account of the reactions of the animal to various 

 chemicals. The reactions were markedly influenced by varia- 

 tions in its " physiological tone." Removal of the ciliated pit 

 of one side of the head caused circus movements toward the 

 intact side. The bilateral disposition of the ciliated pits serves 

 to direct the animal in its movements." The same authors (29) 

 have investigated the food taking of Amoeba proteus. They find 

 much variability in the reactions to food, depending upon the 

 condition of the animal and various external influences 



Lillie and Just (30) have made several interesting observations 

 on the breeding habits of Nereis at Woods Hole, Mass. Breed- 

 ing occurs at certain periods which are influenced mainly by 

 lunar cycles, but which are also affected by several other factors, 

 such as time of day, weather, light and possibly temperature. 

 During the breeding time swarms of both sexes are found swim- 

 ming near the surface and when the females discharge their 

 eggs the males discharge their sperm. The exciting factor which 

 stimulates the males to the discharge of their sperm was shown 

 to be some substance discharged by the egg-bearing females. 



