“The freshwater fish fauna of Florida is one of the most interesting in the United States. It is a fauna developed in a region of recent geologic origin, low topographic relief, poor drainage, and unusual geographic configuration, and consequently exhibits certain very peculiar features. Some of the characteristic continental groups apparently have not had time to establish themselves in the peninsula since its elevation above the sea, while others have doubtless failed to find suitable conditions in its low and swamp-bordered water courses.”