Jacob Theodor Klein's ‘De piscium auditu’ (1740): an early treatise on hearing in fishes, with a description of the form, function and utility of fish otoliths

In ‘De piscium auditu [On the sense of hearing in fishes]’, the first part of Jacob Theodor Klein's Historiae piscium naturalis (1740–1749), Klein provided the earliest specialized treatise on the sense of hearing in fishes. In contrast to many authorities past and present, Klein hypothesized that fishes do indeed hear and that they not only have organs of hearing but also external auditory passages by means of which water-borne sounds are communicated to these organs. His work is reviewed and analyzed, with emphasis on his detailed experimental search for structures comparable to the outer and middle ear of mammals, and his prophetic suggestions regarding the structure, function, and practical utility of the ‘pebbles’ found in the crania of fishes, now known as otoliths.