409 



1899. 



(Table VIII., XII.; PI. XXXIX., L.) 



There are 7 collections at fortnightly intervals in the first 

 3 months of the year, with an average of 1.21 cm. 3 perm. 3 to .41 

 in channel waters. With the exception of four days in Febru- 

 ary, river levels were above 6 ft. throughout the period, and con- 

 sequently the lake was continually receiving water at the north- 

 ern end and discharging at the southern, and contributing 

 throughout the whole time, in this way or through the slough, 

 to channel waters. The average result is an enrichment of the 

 plankton of channel waters. The monthly averages (see table 

 between pp. 342 and 343) in January and February in the lake 

 exceed those in the channel by 9- and 2-fold respectively, while 

 those of March, in highest flood waters, are respectively .28 

 and .21 cm. 3 , owing, as will be seen on a comparison of Plates 

 XIII. and XXXIX., to the distribution of the dates rather than 

 to an actual smaller production. A comparison of all coinci- 

 dent collections in lake and river exhibits likewise a larger 

 plankton content in every instance in lake waters. The lake 

 thus tends continually during this period to enrich by its run- 

 off the plankton content of channel waters. 



The similarity in the movement in production noted in 

 1898 is interrupted in these winter months by dislocations of 

 the apices of the slight pulses of production, due in part to the 

 flushing action of sudden floods and its unequal distribution in 

 channel and backwaters. Of 7 possible agreements in the di- 

 rection of movement in production there are but 3 realized in 

 the case of both the river and Quiver Lake. A comparison of 

 the three plates (XIII., XXIX., and XXXIX.) will, however, 

 show that all, in common, exhibit evidences of a January and 

 a February pulse and a common March decline. 



SUMMARY. 



The grand average of all the Thompson's Lake collections 

 shows a plankton content of 7.94 cm. 3 per m, 3 in comparison with 



