#Fundulus kansae# (Garman): Stations A-2, A-3, Evermann and Fordice as _Fundulus zebrinus_. At station A-2, seven plains killifish were taken together with a great many _Notropis deliciosus_ and _Gambusia affinis_ in a shallow, algae-covered channel with slight flow and sand bottom. At station A-3 many young killifish were taken in small shallow pools on December 22. _Fundulus kansae_ has been found in the lower part of the Walnut River Basin, especially where petroleum pollution was evident. Eastward from the Walnut River plains killifish have not been taken. #Fundulus notatus# (Rafinesque): Stations B-1, G-1, G-2, G-3, G-4, G-5, G-7, G-8, G-10, G-11, G-14, C-1, M-1, E-1, Evermann and Fordice as _Zygonectes notatus_. The black-banded topminnow was not taken in the Arkansas River but was common in the Walnut and Grouse systems. It was common also in Middle Caney, but in Big Caney and Elk River it was taken only at the lowermost stations. This species did not seem to ascend far into smaller tributaries of Grouse Creek. In Crab Creek it was taken at the lower two of six stations and in Grand Summit Creek at the lower of two stations. The highest relative numbers were taken at stations G-3 (17.5 per cent), G-4 (24 per cent), G-10 (25.75 per cent) and G-11 (41.52 per cent), on Crab Creek and Grouse Creek. Both upstream and downstream from these stations, which were within five miles of each other, the relative abundance dropped off sharply. The bottoms at these stations were mostly rubble and mud, and water was turbid at three of the stations. At G-10 (June 24) and G-11 (July 16) young-of-the-year were abundant. #Ictalurus melas# (Girard): Stations W-2, W-3, W-4, W-5, B-1, B-2, B-3, G-1, G-2, G-3, G-4, G-5, G-8, G-9, G-11, G-12, G-13, G-14, G-17, C-1, C-9, C-11, C-12, C-14, C-15, C-17, C-18, E-1, E-2, E-4, E-5, E-6, N-1, Evermann and Fordice as _Ameiurus melas_ (C-133). The black bullhead was taken at slightly more than half of the stations, and probably was present at others. Larger numbers were taken in Grouse Creek than in any other stream system. In many small, shallow pools in the Grouse Creek system young black bullheads shared dominance with _Gambusia affinis_ in the late summer. _I. melas_ was also abundant in isolated pools at the extreme upper ends of Crab Creek, Beaver Creek and Grand Summit Creek. _I. melas_ was most common in areas with silty bottoms. The species seemed scarce in the main stream of Big Caney River but was common in some of its tributaries. #Pylodictis olivaris# (Rafinesque): Stations A-3, G-1, C-5. Flathead catfish were taken by angling at stations A-3 and C-5. At station G-1 (September 5) a flathead catfish five inches long was taken in the four-foot nylon net. #Ictalurus punctatus# (Rafinesque): Stations A-3, W-2, W-3, G-2, C-5, E-4.