18 University of California Puhlicaticns in Zoology [Vol.22 



Its flow is westward. Mormon Channel empties into it about half way 

 up on the south side. Jliner Channel, after traversing the city as an 

 open ditch, empties into it through McLeotl's Lake about three hun- 

 dred yards from the steamer landing. McLeod's Lake is merely a 

 broad slough some four hundred yards in length. It was almost 

 filled with arks and boat houses during 1[)13. All sorts of rubbish 

 and refuse were dumped into Miner Channel and McLeod's Lake at 

 that time, including some sewage from factory drains and some refuse 

 from the tannery. 



The river channel is veiy crooked. The general direction is north- 

 east for about one mile above Station IL At Station II it is nearly 

 east, but within another half mile it has turned to the west. The width 

 is kept fairlj' uniform by dredging and it probably averages one hun- 

 dred and twenty feet near the station. 



Smith Canal is a straight channel about sixty feet wide and two 

 miles long, ending abruptly at the northwest city limits. An open 

 ditch across the northern edge of the city carried waste water from 

 certain gas wells and some sewage directly into its upper end, during 

 most of 1913. This ditch was also partly filled with rubbish and 

 garbage. 



METHODS OP SECURING DATA 

 Time of Collecting 



Most of the collections at Stations II and III were taken at seven- 

 day intervals, at week ends. There was occasional variation of a day 

 or two. Collections at Station I were made twice a week. The mid- 

 week collection was usually on Wednesday. In a few cases there was 

 a change of a day or two in the interval, but there was no failure to 

 make two collections in any week. 



One series of daily collections was taken in Stockton Channel for 

 one month in July and August. Another series of hourly collections 

 was taken for twelve hours in Smith Canal about one mile from the 

 river. The plankton content was slightly different from that of the 

 regular station in Smith Canal, but this was not realized at the time 

 the series was being taken. The difference is not great enough to 

 prevent instructive comparison. 



The time of day at which collections were taken was very variable. 

 Most of tlie midweek collections were taken after school in the late 

 afternoon. Most of the week end collections at all stations were taken 

 in the forenoon. 



