238 REPORT OF COMAnSSIONERS OF INLAND FISHERIES. 



in general; we have, in a preliminary way, during the summer of 1905 

 at the Wickford hatchery, made a brief number of observations to 

 which we hope to add at a later date. 



The records of the experiments cover but a small part of the field 

 of inquiry into the effects of light upon the lobster, inasmuch as they 

 do not consider the subject of the influence of light upon chromato- 

 phore activity and pigment movement, but merely attempt to de- 

 scribe the reactions to light in the first five stages of Homarus when 

 upon backgrounds of black or white; and then to consider briefly 

 the possible influence of light on the rate of development of the lob- 

 ster during its earl 3^ life. 



* 



1. Photopathy in the Larval and Early Adolescent Stages. 



In a previous paper (Science, 1905, XXII, 675) we have used 

 somewhat ill-advisedly the term phototropic to indicate the tendency 

 of organisms to move toward or away from a region of greater light 

 intensity. Believing now, however, that the term phototropism 

 should be used exclusively to represent a tendency on the part of 

 organisms to grow toward the light or away from it, we have considered 

 the terms photopathy and photopathic better adapted to express the 

 nature of the greater number of reactions to be described in the fol- 

 lowing pages — that is, a tendency to move toward or from a region 

 of greater light intensity. We shall also use, together with these 

 terms, the terms phototaxis and phototactic, referring to the tendency 

 of organisms to move in the direction of or opposite to the incident 

 light rays. We consider these terms are here used more advisedly 

 than the older terms heliotropism and heliotropic as used by Loeb, 

 and which give no indication whether the response on the part of the 

 organism concerned may be due to the intensity of the light or to the 

 direction of the light rays, or both. 



We do not assume, however (as does Loeb*), that such phototropic 



*"Heliotropism of Animals," The Decennial Publication of the University of Chicago, vol.1, 

 P, 84. 



