614 The Squamipinnes 
on small crustaceans, worms, and the like. The analogy to the 
butterfly is a striking one, giving rise to the English name, 
butterfly-fish, the Spanish mariposa, and the Japanese chocho- 
uwo, all having the same meaning. Fossil chetodonts are 
rather few, Chetodon pseudorhombus of the Pliocene of France, 
Holocanthus mucrocephalus and Pomacanthus subarcuatus of the 
Eocene, being the only species recorded by Zittel. 
In the principal genus, Chetodon, the colors are especially 
Fie. 508.—Black Angel-fish, Pomacanthus arcuatus (Linneus). Barnegat, 
New Jersey. 
bright. There is almost always a black bar across the eye, 
and often black ocelli adorn the fins. This genus is wanting 
in Europe. Chetodon capistratus, striatus, and numerous other 
species are found in the West Indies; Chetodon humeralis and 
nigrirostris are common on the coast of Mexico. The center 
of their distribution is in Polynesia and the East Indian Archi- 
pelago. Chetodon reticulatus, lineolatus, ulietensis, ornatis- 
simus, ephippion, setifer, and auriga are among the most showy 
species. Numerous closely related genera are described. In 
some of these the snout is prolonged into a long tube, bearing 
4 
