13 



of 1895 ii pliuiktoii station had been established in the west 

 arm of Quiver Lake, known as Dogfish Lake. Examinations 

 were continued in this k)cality for two years at intervals of a 

 month or less, but were discontinued in July, 1897. During 

 much of the year the conditions at this station differed but 

 slightly from those in Quiver Lake. Vegetation is a trifle more 

 abundant and its duration is more extended. Except at times 

 of high water there is no current passing through this arm of 

 the lake. The difficulty of access to this station at times of low 

 water— due to the. dense mat of Ct'ratophyllum through which 

 thf plankton boat must be rowed — were increased by the erec- 

 tion of a fence of wire netting across the mouth of the lake in 

 the construction of a fish pound. In view of the similarity to 

 (Quiver Lake and the difficulty of access, it seemed desirable to 

 drop this station from the regular list, especially as the two 

 years' collections of its micro-flora and micro-fauna will suffice 

 for detailed comparison with the plankton of the main body of 

 the lake. 



Monthly plankton collections were made in Thompson's 

 Lake during the first half of 1897, but in July of that year a 

 fortnightly interval was adopted and has since been maintained. 

 This station is, next to the river, the most important one on our 

 list, being located in the largest permanent body of water within 

 the field of our operations. During the period of high water 

 (three to four months of the year), it is of easy access, as it 

 is possible at such times to run the launch through the "cut 

 road" across the bottomlands to the south end of the lake. As 

 the water falls access may still be had for some time with a row 

 boat through the " cut road;" or, at still lower water, through 

 the "swale," a tortuous channel through the bottomland under- 

 brush from the foot of Flag Lake to Thompson's Lake. When, 

 however, the river falls below six feet, the only approach to this 

 station is via Thompson's Lake Slough, a bayou connecting the 

 lake with the river, leaving the latter at a point about six miles 

 above Havana. Shallow water and a rank growth of aquatic 

 vegetation found in some years at the northern end of the lake 

 soon render it impossible to enter from the slough with the 

 launch, and when the water falls below three feet a mud bar at 

 the northern end of the slough necessitates making the remainder 



