Acanthurus triostegus, _Cuv. et Val._ Hist. des Poiss. tom. x. p. 144.
—— Hirudo, _Benn._ Fish of Ceyl. pl. xi.
This species, which appears to be well known, and to have been described
by several authors, was found by Mr. Darwin on coral reefs at the
Keeling Islands. Cuvier and Valenciennes observe that it has a wide
range through the Indian and Pacific Oceans. Mr. Darwin’s specimen
agrees in every respect with the description in the “Histoire des
Poissons,” except in having one ray more in the anal fin: its length is
not quite five inches.