244 Journal of Comparative Neurology and Psychology. 



C^j^ 5 — One observation on the behavior of the early fourth- 

 stage lobsters is difficult to harmonize with the reactions mentioned 

 in the previous cases. When at night the rays from an acetylene 

 light were brought to bear upon very early fourth-stage lobsters, 

 swimming in the confinement bags, they would sometimes swim 

 directly toward the light. This reaction was often so strongly 

 manifested that the natural rheotactic response to the influence 

 of the water current circulating in the bags was quite obscured in 

 the areas of greatest illumination, because the young lobsters fol- 

 lowed — so to speak — the course of the rays from the acetylene 

 lantern. If this reaction represents a true phototactic response, 

 then it must be said that very early fourth-stage lobsters may, 

 under appropriate conditions of stimulation, respond positively 

 to the directive influence of light, not, as do the earlier stages or 

 the late fourth-stage by turning from the light, but by "heading" 



