--------------------+--------+--------+---------+---------- Some fish were almost restricted to the sandy streams, apparently because of preference for larger waters, or sandy stream-bottoms: _P. olivaris_, _I. bubalus_, _H. nuchalis_, _H. aestivalis_, _A. grunniens_, _L. osseus_, _D. cepedianum_, _N. percobromus_, _P. annularis_, _N. flavus_, _M. aureolum_, _I. niger_, _H. alosiodes_, and _R. chrysops_. Other species that were taken only in the larger rivers, and that are sometimes associated with streams even larger (or more sandy) than the Big Blue River are _H. storeriana_, _L. platostomus_, _M. salmoides_, _P. nigromaculatus_, _C. forbesi_, _S. platorynchus_, _F. kansae_, _N. buchanani_, _S. canadense_, and _C. auratus_. _Ictiobus cyprinella_ also occurred more frequently in the larger streams. The muddy-bottomed streams supported populations composed primarily of _P. promelas_, _N. lutrensis_, and _S. atromaculatus_. No species was restricted to this habitat, but the following were characteristic there: _P. promelas_, _S. atromaculatus_, _L. humilis_, _L. cyanellus_, and _I. natalis_. _Carpiodes carpio_, _Cyprinus carpio_, _C. anomalum_, _E. spectabile_, and _E. nigrum_ were locally common in muddy streams, but the first two were most frequent in larger, sandy streams, and the last three in gravelly streams. In gravel-bottomed, upland streams, _N. cornutus_, _N. rubellus_, _N. topeka_, and _C. erythrogaster_ characteristically occurred; with the exception of _N. rubellus_ (only one specimen taken), all were common at some stations. Other species in gravelly creeks were _N. lutrensis_, _C. anomalum_, _C. commersonnii_, _P. notatus_, _L. macrochirus_, _E. spectabile_, and _E. nigrum_. Although the one specimen of _N. umbratilis_ taken in this survey was from the Big Blue River, this species is more characteristic of the clearer creeks in Kansas. In order to illustrate the composition of the fauna in some specific streams in the Big Blue River Basin, I segregated the fishes into ecological groups, as in the above discussion: ubiquitous types; species of larger, sandy streams; fishes of muddy streams; and fishes of clear, gravelly creeks. The total number of species taken in each of the streams was divided into the number of species from that stream that were in each of these units, to give a percentage. The resultant data are presented graphically in Figure 3. [Illustration: FIG. 3. Composition of the fauna of the entire Big Blue River Basin, and of seven streams or stream systems in that basin. "Mill Creek, Wash. Co." refers to all streams in the Mill Creek System, Washington and Republic counties. "Bl. Vermillion R. System" includes all streams in that watershed excepting Clear Creek and one of its tributaries (Stations 31-G and 32-G).]