The length-frequency distribution of 438 channel catfish, collected by rotenone on August 5 and 7, 1958, indicated that two age-groups were represented. Without examination of spines, I assigned 265 fish to age-group O (1.3 to 2.9 inches, average 2.5) and 173 fish to age-group I (3.1 to 5.8 inches, average 4.5). The average total length of age group I (4.5 inches) is only slightly higher than the total length at the first annulus reported as average for Oklahoma (4.0 inches, Finnell and Jenkins, _loc. cit._). It seems unlikely that my yearling fish taken in August, 1958, would have reached the length at the second annulus recorded in my study of spines (7.3 inches) by the end of the 1958 growing season. From 1952 to 1956, severe drought was prevalent in Kansas, probably causing streams to flow less than at any previously recorded time (Minckley and Cross, in press). This drought must have resulted in reduced populations of fishes in the streams. The channel catfish hatched in 1956 were therefore subjected to low competition for food and space when normal flow was resumed in 1957, and grew rapidly, reaching an average total length of 7.3 inches at the second annulus, while channel catfish that were members of the large 1957 and 1958 hatches suffered more competition and grew more slowly. =Noturus flavus= Rafinesque, stonecat: Jennings (1942:365). Stations 3-S, 4-S, 6-S, 16-G, 25-S, 28-G, 38-S, 41-S, 42-S, 43-S, 52-S, 53-S, and 56-S. _Noturus flavus_ frequented riffles and swift currents along sandbars in the Big Blue and Little Blue rivers. Cross (1954:311) reported that "the shale-strewn riffles of the South Fork [of the Cottonwood River, Kansas] provide ideal habitat for the stonecat." In my study-area, this species was found not only on rubble-bottomed riffles, but occurred along both stationary and shifting sandbars where no cover was apparent. =Pylodictis olivaris= (Rafinesque), flathead catfish: Canfield and Wiebe (1931:7) as "yellow catfish." Stations 3-S, 4-S, 6-S, 8-S, 15-S, 25-S, 38-S, 41-S, 43-S, 44-S, 53-S, and 56-S. Flathead catfish were found only in the larger rivers. The species was taken rarely by seine, but was readily obtained by electric shocker. Data on the age and growth and food-habits of this species are to be the subject of another paper. =Anguilla bostoniensis= (LeSueur), American eel: Jennings (1942:365). American eels are now rare in Kansas, and none was taken in my survey. The specimen reported by Jennings (_loc. cit._) is at Kansas State College (KSC 2916), and was taken by I. D. Graham from the Big Blue River, Riley County, 1885. =Fundulus kansae= Garman, plains killifish. Station 42-S. The plains killifish was collected by me only at Station 42-S. Specimens were collected from my Station 4-S by the Kansas State College class in fisheries management in 1954 (KSC 4985). My specimens were 11 to 13 mm. in total length. =Roccus chrysops= (Rafinesque), white bass. Station 3-S.