The orange-spotted sunfish occurred at all stations; it was most abundant in the Neosho River, especially at the uppermost station. This fish was taken in a variety of habitats, but was most common in areas where the current was slack, often over mud or silt bottom. #Lepomis macrochirus# Rafinesque Bluegill Bluegill were taken at all stations but were rare. This species occurred exclusively in pools, usually near cover (brush or trees in the water). Bluegill are predominately pond-fish in Kansas, and populations in rivers may consist partly of individuals that escaped from ponds in time of overflow. I know of no stream in Kansas that has a population large enough to contribute significantly to the sport fishery. #Pomoxis nigromaculatus# (LeSueur) Black Crappie This species was represented by only one specimen, taken at the lower Neosho station in 1957. #Pomoxis annularis# Rafinesque White Crappie White crappie were taken at all stations, but were common only at the upper and middle stations on the Marais des Cygnes and the upper Neosho station. At the last station, this fish was abundant in a single large pool that contained much more water during drought than any other area at this station. There was little dispersal into several smaller pools, below the large pool, which were sampled in 1957, 1958 and 1959. White crappie were not taken in the lower pools until 1959, and then were rare. Most crappie were taken in quiet water near cover or near shore. Young-of-the-year were found in 1957, 1958 and 1959, but never abundantly. At the lower Neosho station in 1959, ripe individuals were collected on 19 June, a spent female on 24 June, and young-of-the-year on 1 July. The young were present in quiet, shallow water over mud bottom at the lower end of a gravel bar. Large white crappie (10-14 inches T. L.) were common at the middle and lower Neosho stations in 1957 and in April, 1958. Large fish were almost entirely absent from later collections. Average size, maximum size and abundance declined during the period of study. #Percina phoxocephala# (Nelson) Slender-headed Darter The slender-headed darter was taken at all stations but was more abundant in the Neosho than in the Marais des Cygnes. The lower Marais des Cygnes, however, was the only station with a relatively large population in 1957. Slender-headed darters were rare in the Neosho River in 1957 and did not become common until 1959. The largest population was found at the upper Neosho station in 1959. This darter occurs most frequently in swift water over gravel bottom, but was taken in various habitats, including an intermittent pool at the upper Neosho station on 7 September, 1957. At the middle and lower Neosho stations, considerably greater numbers were taken in June, July, and early August than in May or late August. The abundance in my collections diminished from a peak in early July, to scarcity in late August.