Geographic Variation in the North American Cyprinid Fish, Hybopsis gracilis

"Geographic Variation in the North American Cyprinid Fish, Hybopsis gracilis" by Leonard J. Olund is a scientific exploration of the flathead chub, a North American fish, from the early 1960s. It examines where different types of this fish live and how they look in different environments. The book discusses what the flathead chub eats, how it reproduces, and its behavior. It explains that there are two main types: one that lives in bigger rivers and another adapted to smaller streams. Through careful study and measurements, the authors reveal how the fish's physical traits and lifestyles change based on where they live, providing key details about this fish's life story and its interactions with its surroundings.