=The Spadefishes: Ilarchidæ.=—In the _Ilarchidæ_ the dorsal is divided into two fins, the spinous part being free from scales. In various regards the species are intermediate between ordinary perch-like forms and the chætodonts. In these fishes the body is very deep and, with the soft fins, closely covered with roughish scales. In _Ilarches_ (_Ephippus_), represented by _Ilarches orbis_ of the Indian seas, these scales are relatively large. This species is a common food-fish from India to Formosa. In the American genus, _Chætodipterus_, the scales are quite small. The spadefish (_Chætodipterus faber_), sometimes called also moonfish or angel-fish, is a large, deep-bodied fish, reaching a length of two feet. It is rather common from Cape Cod to Cuba, and is an excellent pan fish, with finely flavored white flesh. The young are marked by black cross-bands which disappear with age, and in the adult the supraoccipital crest is greatly thickened and the skull otherwise modified. A very similar species, _Chætodipterus zonatus_, occurs on the west coast of Mexico. Species allied to _Chætodipterus_ are fossil in the Italian Eocene. The _Drepanidæ_ of the East Indies are close to the _Ilarchidæ_. _Drepane punctata_ is a large, deep-bodied fish resembling the spadefish but with larger scales. [Illustration: FIG. 337.—Spadefish, _Chætodipterus faber_ (L.). Virginia. ] =The Platacidæ.=—Closely related to the _Ilarchidæ_ is also the East Indian family of _Platacidæ_, remarkable for the very great depth and compression of the body, which is much deeper than long, and the highly elevated dorsal and anal still further emphasize this peculiarity of form. In this group the few dorsal spines are closely attached to the soft rays and the general color is dusky. In the young the body is deeper than in the adult and the ventral fins much more produced. The best-known species is the tsuzume or batfish (_Platax orbicularis_), which ranges from India through the warm current to northern Japan. _Platax teira_, farther south, is very similar. _Platax_ _altissimus_, with a very high dorsal, is a fossil in the Eocene of Monte Bolca. [Illustration: FIG. 338.—Butterfly-fish, _Chætodon capistratus_ Linnæus. Jamaica. ]