CONTINUED OBSERVATIONS ON SOME INFLUENCES OF 



LIGHT UPON THE LARVAL AND EARLY ADOLESCENT 



STAGES OF THE AMERICAN LOBSTER. 



CONTINUED REPORT. 



BY PHILIP B. HADLEY. 



BROWX tTNlVEBSITT, PROVIDENCE, R. I. 



The advantage of investigating the influences of light upon the 

 lobster in the early stages of development has been mentioned by 

 the writer in an earlier report.* 



The present paper is presented with the purpose of giving the 

 results of continued investigation on the reactions of the larval and 

 early adolescent lobsters to light; and with the view of applying the 

 facts thereby gained to the explanation of certain phases of the 

 behavior of the young lobsters when they are under natural condi- 

 tions of environment. 



This study of the reaction to light naturally divides itself into 

 two parts : First, the reactions proper (positive or negative to the in- 

 tensity or to the directive influence of the light) ; secondly, what may 

 be called the mechanics of reaction. The first of these two heads is 

 subdivided into (1) the study of the photopathic reactions (the 

 reactions to the intensity of light), and (2) the phototactic reactions 

 (the reaction to the directive influence of the light rays). We may 

 first limit our discussion to a consideration of the reactions proper, 

 and then turn our attention to the second phase of the question, the 

 mechanics of reaction. 



♦Report of the Rhode Island Commission of Inland Fisheries for 1905. 



