2o6 'Journal of Comparative Neurology and Psychology. 



placed a box 2 feet high, 3 feet wide, and 2 feet deep, Hned on the 

 inside with black cloth, and containing, on the window side, slits 

 or openings to correspond with the openings in the screen outside 

 the box. On the room side, the box was fitted with a movable 

 black curtain, which permitted the operator to move the jars or 

 other apparatus contained within the box. This arrangement 

 served to control the light falling upon the larvae, which were put 

 in suitable containers and placed inside the box. 



Other pieces of apparatus may be described as follows: Glass 

 box A. Of glass boxes two types were used for studying the pho- 

 topathic and phototactic reactions of the larvae. One was a rec- 

 tangular wooden box having glass "windows" in each end and 

 in the bottom. This box, which was 12 inches long, 6 inches wide, 

 and 3 inches deep, was painted dull black on the inside and fitted 

 with a light-tight cover. It was used in experiments which re- 

 quired illumination from the end, from below, or both. 



Glass box B — This box was similar in most respects to box A 

 (see Fig. 7). It was 12 inches long, 6 inches wide, and 5 inches 

 deep. It had "windows" on each end and along one side. Like 

 box A, it was painted black on the inside and was fitted with a 

 light-tight cover. This cover contained three slits so arranged that 

 diaphragms of wood or glass might, in an instant, be slid into place 

 to divide the box transversely into four chambers of equal extent. 

 Then the cover of the box might be removed if desired, leaving 

 the partitions in place. The object of this arrangement was to 

 make it possible to imprison the young lobsters wherever they 

 chanced to be at any given time and so to ascertain, by count, in 

 what manner and in what relative numbers they had responded 

 to certain stimuli. 



Of these two boxes, the former, while oftener placed in a level 

 position on a laboratory table, was sometimes used in another way 

 to study the photopathic reaction alone, or the photopathic and 

 the phototactic reactions together. In these cases the box was 

 placed over a light-shaft, which was merely a rectangular tube 

 lined with black cloth, with a height of 18 inches and with a cross 

 section of the same size as the bottom of the box. Over the upper 

 end of this tube or shaft, the glass bottom of box A exactly fitted. 

 At the bottom of the shaft was either a sheet of white paper or a 

 mirror which was so placed as to reflect the rays of light coming 

 from the w^indow up through the shaft to the glass bottom of the 



