18 University of California Publications in Zoology [Vol.19 



so on, to the number in the bottom section, at the right. At 11 :20 a.m. 

 the distribution was 1, 1, 0, 0, 6; at 12:45 p.m. and 12:55 p.m. it was 

 0, 0, 0, 0, 8. Then the tube was turned horizontal, so that what was 

 the lower section became the one next the window. The animals all 

 swam away from the light, and when they were in the section opposite 

 the window, the tube was turned to the vertical position, at 1 :33 p.m. 

 This brought all the specimens into the top section. The distribution 

 at intervals follows: 1:35 p.m., 1, 1, 1, 2, 3 ; 1:37 p.m., 1, 0, 1, 1, 5; 

 1 :38 p.m., 0, 1, 0, 1, 6 ; 1 :39 p.m., 0, 1, 0, 0, 7 ; 1 :40 p.m., 0, 0, 1, 0, 7 ; 

 1 -.41 p.m., 0, 0, 0, 1, 7 ; 1 :42 p.m., 0, 0, 0, 0, 8. At this point the room 

 was made dark and the 15-watt lamp was placed ten centimeters from 

 the bottom of the tube. None of the animals left the bottom in seven 

 minutes of continuous observation. The tube was inverted then (so 

 that all the animals were in the top section) and the 15-watt at the 

 top of the tube was turned on at 1 :56 p.m. At 2 :00 p.m. the distribu- 

 tion was 2, 1, 1, 0, 4; at 2:03 p.m., 2, 0, 2, 1, 3; at 2 :07 p.m., 1, 0, 1, 1, 5 

 at 2:10 p.m., 1, 0, 0, 0, 7. Here the light was cut off, and at the end 

 of ten minutes in darkness the distribution was still 1, 0, 0, 0, 7. Evi- 

 dently the animals did not ascend in darkness. Then at 2:21 p.m. the 

 tube was inverted again, putting seven animals in the top and one in 

 the bottom section and darkness was continued. At 2:25 p.m. the dis- 

 tribution was 0, 0, 2, 3, 3 ; at 2:28 p.m., 0, 0, 0, 0, 7 ; at 2:43 p.m., 0, 0, 

 0, 0, 7 ; at 3 :00 p.m., 1, 0, 0, 1, 6 ; at 3 :20 p.m., 2, 1, 2, 0, 3 ; at 3 :45 p.m., 

 2, 0, 1, 0, 5 ; at 4 :00 p.m., 2, 0, 0, 0, 6 ; at 5 :25 p.m., 5, ?, ?, ?, 2 ; at 8 :00 

 p.m., 6, 1, ?, ?, 1. 



"While these details are intended chiefly to show the positive geo- 

 tropism of deep water animals, they incidentally reveal negative photo- 

 tropism, and the onset of negative geotropism about 6:00 p.m. This 

 latter point has been dealt with in another place (Esterly, 1917&, 

 p. 396, table 3). There is no reason to doubt that the behavior shown 

 by the animals from deep water is characteristic of the species, but 

 the data might well be more extensive. 



In contrast to the behavior of the deep-water specimens animals 

 from the surface are negatively geotropic in the diffuse light of a room 

 and positive in darkness. Since one could not depend upon getting 

 surface animals except at night it was necessary to leave the experi- 

 mental specimens in the laboratory for a few hours at least. A few 

 preliminary tests indicated that individuals from the surface react at 

 once as they do after six or eight hours, and I have assumed, therefore, 

 that retention in the laboratory does not affect the behavior of animals 



