The peritoneum is mottled dark and silvery in the hybrids; it has a composite of the coloration in the parental species rather than a blended shade. The intestine has two diagonal loops crossing the ventral part of the body cavity, and the hindgut lies high in the cavity, along the left side of the air bladder. In _Campostoma_, the long gut is transversely coiled around the air bladder, whereas in _Semotilus_ the gut forms a longitudinal, flattened, S-shaped loop, ventral to the air bladder. In the hybrids, the mouth is slightly oblique and nearly terminal. The lower lip is thick and fleshy, but has only a suggestion of the projecting mandibular shelf that is unique in _Campostoma_. The upper lip is uniform in width, not medially expanded as in _S. atromaculatus_. One of the hybrids lacks barbels, one has a _Semotilus_-like barbel on the right side only, and one has a vestigial barbel on the right side and an anomalous barbel that is nearly terminal on the left upper lip. In coloration, the hybrids lack the spot in the anterior base of the dorsal fin that is characteristic of _Semotilus_, but each has a poorly-developed dark lateral band, and a weak basicaudal spot. This band and spot are usually prominently developed in _S. atromaculatus_ and usually are absent in adults of _C. a. plumbeum_. In the position and obliquity of the mouth, basic color pattern (diffuse lateral band and basicaudal spot), and the presence in one specimen of a nearly terminal, barbel-like structure, the hybrids somewhat resemble _Hybopsis biguttata_ (Kirtland), which occurs rarely in the Kansas River Basin. These partial similarities are coincidental, because other characters of the hybrids make relationship with _H. biguttata_ implausible. The high number of gill rakers (Table 3) and the length and position of the gut indicate strongly that the three specimens are hybrids with _C. anomalum_ as one parent; the pharyngeal arches, though deformed, indicate that the other parental species has two rows of teeth, with five teeth in the main row. Only _S. atromaculatus_, among species in the Kansas River Basin, usually has such a dental formula, and other characters of our three specimens fit expectations in a hybrid between that species and _C. a. plumbeum_. Timber Creek, where the three hybrids were collected, is a small, spring-fed, sandy-bottomed tributary to Scott County State Lake in the extreme southwestern part of the Kansas River Basin. The stream was less than 10 feet wide and six inches deep, except in three pools near road crossings. The hybrids were found in two of these pools, along with numerous _S. atromaculatus_ and one adult _C. a. plumbeum_.