256 



REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



to three days longer than in any other group of lobsters which were 

 reared under different conditions during the same or during the 

 previous summer. 



Table No. 4. 



Showing the average per cent, of increase for lobsters in the fifth, sixth, seventh, 

 and eighth stages raised under different conditions of light. 



* This group was raised in wire cylinders in direct sunlight. 



t Lobsters which were kept in wire cylinders, and protected by a framed canvas sUghtly 

 above the cylinders. 



t Lobsters which were kept in narrow compartment cars, which admitted no Ught on the 

 sides and but httle on the top. 



§ Selected lobsters which were kept in wooden cars covered so that but little light was ad- 

 mitted from any direction. 



If the influence of sunlight is able to cause such differences in the 

 rate of development of lobsters in the fourth stage, it is not unreason- 

 able to believe that the same influence may be, if anything, more 

 detrimental to the development during the early larval stages. 



One other factor which is commonly recognized as being able to 

 greatly diminish the rapidity of growth, especially in the early stages, 

 is the accumulation of diatoms, protozoa, and algse which not infre- 

 quently gathers on the bodies of the young lobsters. There can be 

 but little doubt that the profusion of this growth is, in a great meas- 

 ure, directly dependent upon the degree of light intensity to which 



