302 Illinois State Laboratory of Natural History. 



half a mile below Havana, west of the river, is situated 

 Phelps Lake, which is merely a shallow depression something 

 over half a mile long and less than a quarter of a mile wide, 

 surrounded by woodland, and usually filled with water to a 

 depth of one or two feet ; near its upper end F is located. 

 G is in the southern part of Thompson's Lake, a large per- 

 manent body of water, about five miles long and over half a 

 mile wide, with a depth at low water of about four feet, lying to 

 the west of the river above Havana. K is located near the 

 middle of Flag Lake, which is a large but very shallow body 

 of water, about three miles long and half a mile wide, lying 

 between Thompson's Lake and the Illinois River, and full of 

 coarse "flags" — Scirpus, Sagittaria, etc., — Nymphced, Nelumbo, 

 and Ceratophyllum. L is situated in Dogfish Lake, which 

 opens into the west side of Quiver Lake, and is about a mile 

 long and a quarter of a mile wide, and somewhat shallower 

 than Quiver Lake at C. Collections were also made in the 

 "Pumpkin Patch," a small marshy bay communicating with 

 Quiver Lake at its head, and in Matanzas Lake, just east of 

 the river, about three and a half miles south of Havana. 



Studies of the Protozoa and Rotifera at the Biological Sta- 

 tion were begun respectively in the latter part of April and 

 of May, 1894. This work was carried on at the Station 

 throughout the season until September 10, and all subse- 

 quent catches from that date to April 1, 1896, were examined 

 and a record was kept of the Protozoa and Rotifera found in 

 them. The period of time thus covered was about two years, 

 the interval between the collections varying from a week to 

 two months. The results of this work form the basis of the 

 present article. Several species which were first noticed later 

 than April, 1896, are incorporated in their proper place. The 

 list is intended primarily as a record of the Protozoa and 

 Rotifera found in the general collections made at the various 

 substations, and in but few instances were data obtained from 

 other sources. Doubtless the number of species recorded 

 would be considerably greater if the time had been spent in 

 endeavoring to list as many forms as could be found, regard- 

 less of substations. As it was, there were two difficulties 



