1911] Michael: Chaetoguatha of the San Diego Region. 125 



second 6, and the third 4 specimens of S. bipunctata. Expressed according 

 to hour-hauls the numbers are 360, 6, and 4. Thus, from 44 minutes before 

 till 16 minutes after sunrise the number of specimens on the surface de- 

 creased in the proportion of 90 to 1. 



13. On July 10, 1909, the sun rose at 4:59 a.m. Haul 1888 lasting from 

 4:35 to 5:20 a.m. contained 132, and haul 1892 lasting from 5:25 to 5:55 

 a.m. contained 15 specimens of S. bipunctata. Expressed according to hour- 

 hauls the numbers are 176 and 30. Hence, from 39 minutes before till 56 

 minutes after sunrise the number of specimens on the surface decreased in 

 the proportion of 6 to 1. 



To emphasize the bearing of the thirteen instances just cited 

 I have condensed the data into the following table. 



