Note 1762 — BOOK VIII. THE NATURE OF THE TERRESTRIAL ANIMALS.
John Bostock translation
The water of the Nile abounds with small leeches, which attach to the throat of the crocodile, and, as it has no means of removing them, it allows a little bird to enter its mouth for this purpose; this is described by Aristotle, Hist. Anim. B. ix. c. 6, and by Ælian, Anim. Nat. B. iii. c. 2.—B.