Louis Roule - Fishes and Their Ways of Life (1935)
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A somewhat bland title for a slightly unusual look at swimming critters (not all fish). For one thing there's a whole chapter on the fish that go into bouillabaisse, another on electric fish, another on shark's teeth, all in a somewhat elaborate but not overdone prose (translated from French). Not a royal road to ichthyology but more like the scenic route.