Collections were made by means of: (1) a four-foot net of nylon screen; (2) a 10x4-foot "common-sense" woven seine with 1/4-inch mesh; (3) a 15x4-foot knotted mesh seine; (4) a 20x5-foot 1/4-inch mesh seine; (5) pole and line (natural and artificial baits). At most stations the four-foot, ten-foot, and twenty-foot seines were used; however, the equipment that was used varied according to the size of pool, number of obstructions, nature of bottom, amount of flow, and type of streambank. Usually several hours were spent at each station and several stations were revisited from time to time. Percentages noted in the List of Species represent the relative number taken in the first five seine-hauls at each station. COLLECTING STATIONS Collecting was done at stations listed below and shown in Fig. 2. Each station was assigned a letter, designating the stream system on which the station was located, and a number which indicates the position of the station on the stream. This number increases progressively upstream from mouth to source. Code letters used are as follows: A--Arkansas River; W--Walnut River System; B--Beaver Creek System; C--Big Caney River System; G--Grouse Creek System; M--Middle Caney Creek System; E--Elk River System. All dates are in the year 1956. [Illustration: FIG. 2. Map of Cowley, Chautauqua and Elk counties, Kansas, showing stations at which collecting was done.] A-1. Arkansas River. Sec. 2 and 3, T. 35 S, R. 4 E. June 14 and August 20. Braided channel with sand bottom. Water slightly turbid, with layer of oil sludge on bottom. A-2. Arkansas River. Sec. 22, T. 34 S, R. 3 E. August 25. Flowing through diverse channels. Average depth 12 inches. Bottom sand. (Plate 9, fig. 1.) A-3. Arkansas River. Sec. 21, T. 33 S, R. 3 E. August 27 and December 22. Flowing over fine sand. Average depth 11 inches. Some areas of backwater with oil sludge on bottom. W-1. Walnut River. Sec. 20, T. 34 S, R. 4 E. July 7. Flowing rapidly, with large volume, because of recent rains. Average width 300 feet. Bottom gravel. Water turbid. W-2. Walnut River. Sec. 11, T. 34 S, R. 4 E. July 20. Rubble riffles and large shallow pools with gravel bottoms. Average width, 100 feet. Water clear. W-3. Walnut River. Sec. 29, T. 32 S, R. 4 E. July 17. Pools and riffles below Tunnel Mill Dam at Winfield. Water clear. W-4. Badger Creek. Sec. 6, T. 33 S, R. 5 E. July 17. Small pools. Average width 7 feet, average length 40 feet, average depth 8 inches. Water turbid and malodorous. Bottoms and banks mud. Much detritus present. W-5. Timber Creek. Sec. 35, T. 31 S, R. 4 E. June 6. Intermittent pools, widely separated. Average width 9 feet, average depth 8 inches. Bottom mud and gravel. B-1. Big Beaver Creek. Sec. 8, T. 35 S, R. 7 E. May 28. Isolated pools. Average width 10 feet, average depth one foot. Water turbid. Bottom rubble.