76 



a number of examinations were made at frequent intervals during a remark- 

 able development of a filamentous diatom, Melosiru, in the plankton, and in 

 correlation with gas analyses conducted by Professor Palmer. Weekly col- 

 lections upon Tuesdays were begfun August 3, 1896, and have since been 

 maintained except when the condition of the ice or sickness necessitated a 

 slight shifting of the day of collection. ^ 



The station in Quiver lake was visited during intervals of one month during 

 the first half of 1897, but during the latter part of July and the months of August 

 and September the interval was reduced to a week. In October fortnightly 

 visits were commenced, and have since been maintained. In the summer 

 of 1895 a plankton station had been established in the west arm of Quiver 

 lake, known as Dogfish lake. Examinations were continued in this locality 

 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 cur- 

 rent 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 Cemtophj/llum through 

 which the plankton boat must be rowed — were increased bj' the erection of a 

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

 fish pond. In view of the similarity to Quiver lake and the difficulty of ac- 

 cess, it seemed desirable to drop this station from the I'egular 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 bottom lands 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 underbrush 

 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 slouo:h 

 necessitates making the reraaiuder of the trip in a row boat. During the 

 months of September, October, and the most of November, 1897. the river 

 stood at the present low water mark, that is, about two feet by the guage. and 

 the lake was drained to the lowest limit reached since our operations were 

 commenced at Havana. Its bed at the north end, for a distance of about 

 three quarters of a mile, was exposed, leaving an expanse of the softest black 

 ooze, through which a narrow, wind'ug channel several feet in width, contain- 

 ing several inches of water, was kept open by our boats and those of occas- 

 ional sportsmen. When winds from the north prevailed, even this insignifi- 

 cant highway was left bare. Under these conditious it^gress and egress over 

 and through this bed of ooze became a task of no small difficulty. 



Owing to these two routes of approach to the lake, two points of collection 

 have been established; one off Sand Point, in the northern half, and one 

 about half a mile below Prickett's Landing, in the southern half. Both are 

 in open water and at a considerable distance from vegetation, and are equally 

 typical locations. Access to one of these two places is always possible during 

 the period of open water or when the lake is covered with thick ice. but when 

 the ice is thin or rotten, it is at times only possible to work out a few rods 

 from the shore with the aid of ax and ice-hook. 



Plankton operations were not carried on in Phelps lake in 189.1. owing to 

 the failure of the river to overflow the bottomlands sufficiently to invade and 

 fill the lake. During this year a heavy crop of corn was raised in its fertile 

 bed, but before it was harvested the following winter the water asserted its 

 claim to this territory and has since held possession. The rise which eulmi- 



