Aipichthys, one of the few Acanthopterygian types known to have existed in the Cretaceous period, appears to belong to the family Scorpididae as here defined, and not to the Carangidae.
Fam. 26. Caproidae.—Characters of Scorpididae, but supratemporal completely ankylosed to the skull.
The Boar-Fish (Capros aper) of the Atlantic and Mediterranean is occasionally found on our southern coasts, and is highly remarkable for the hair-like bristles with which its scales are covered, an extreme exaggeration of the "Ctenoid" type. The mouth is very protractile, and the vertebrae are only 22 or 23 in number. Antigonia, with a single species found at remote points in the Atlantic, Pacific, and Indian Oceans, is probably allied to Capros, with which it is believed to be connected through the fossil genus Proantigonia, from the Upper Miocene of Croatia.
Fig. 408.—Psettus sebae, from the West Coast of Africa, × ½.
Fam. 27. Chaetodontidae.—Closely allied to and evidently derived from the more generalised types of the Scorpididae, differing in the attachment of the gill-membranes to the isthmus. Post-temporal more or less firmly united with the skull, sometimes indistinctly bifurcate. Mouth small; palate toothless; soft portions of vertical fins usually covered with scales; ribs usually strong and blade-like; body short and deep.
A large group of about 200 marine carnivorous fishes from the tropics, mostly of small size, remarkable for their singular forms and markings and brilliant coloration. They are particularly abundant about volcanic rocks and coral reefs.
An Atlantic species of Ephippus (E. faber) is extremely remarkable, when adult, for an enormously enlarged globular bony mass on the back of the head, formed by hypertrophy of the frontal and supraoccipital bones.
Principal genera: Ephippus, Parapsettus, Scatophagus, Chaetodon, Chelmo, Heniochus, Holacanthus, Pomacanthus, Platax.
Chaetodon, Holacanthus, Pomacanthus, Scatophagus, Ephippus, and Platax were represented in the Eocene of Europe.