The genus Holocentrus is characterized by the presence of a large spine on the angle of the preopercle. Its species are especially numerous, Holocentrus ascenscionis, abundant in Cuba, ranges northward in the Gulf Stream. Holocentrus suborbitalis, the mojarra cardenal, is a small, relatively dull species swarming about the rocks of western Mexico. Holocentrus spinosissimus is a characteristic fish of Japan. Many other species abound throughout Polynesia and the East Indies, as well as in tropical America. Holocentrus ruber and Holocentrus diadema are common species of Polynesia and the East Indies. Other abundant species are H. spinifer, H. microstomus, and H. violascens.
Holocentrus marianus is the marian of the French West Indies. Holocentrus sammara, and related large-mouthed species occur in Polynesia.
Fig. 204.—Ostichthys japonicus (Cuv. & Val.). Giran, Formosa.
In Myripristis the preopercular spine is wanting and the air-bladder is divided into two parts, the anterior extending to the ear. Myripristis jacobus is the brilliantly colored candil, or "Frère Jacques," of the West Indies. Species of Myripristis are known in Hawaii as u-u. A curious method of catching Myripristis murdjan is pursued on the Island of Hawaii. A living fish is suspended by a cord in front of a reef inhabited by this species. It remains with scarlet fins spread and glistening red scales. Its presence is a challenge to other individuals, who rush out to attack it. These are then drawn out by a concealed scoop-net, and a fresh specimen is taken as a decoy. Myripristis pralinius, M. multiradiatus, and other species occur in Polynesia. Ostichthys is allied to Myripristis but with very large rough scales. Ostichthys japonicus is a large and showy fish of the waters of Japan. Ostichthys pillwaxi occurs at Honolulu. Holotrachys lima is a small, brick-red fish with small very rough scales found throughout Polynesia.
Fossil species of Holocentrus, Myripristis, and related extinct genera occur in the Eocene and Miocene. Holocentrus macrocephalus, from Monte Bolca Eocene, is one of the best known. Myricanthus leptacanthus from the same region, has very slender spines in the fins.
Fig. 205.—Pine-cone Fish, Monocentris japonicus (Houttuyn). Waka, Japan.
The Polymixiidæ.—The family of Polymixiidæ, or barbudos, is one of the most interesting in Ichthyology from its bewildering combination of characters belonging to different groups. With the general aspect of a Berycoid, the ventral rays I, 7, and the single dorsal fin with a few spines, Polymixia has the scales rather smooth and at the chin are two long barbels which look remarkably like those of the family of Mullidæ or Surmullets. As in the Mullidæ, there are but four branchiostegals. In other regards the two groups seem to have little in common. According to Starks, the specialized feelers at the chin are different in structure and must have been independently developed in the two groups. In Polymixia, each barbel is suspended from the hypohyal; three rudimentary branchiostegals forming its thickened base. In Mullus, each barbel is suspended from the trip of a slender projection of the ceratohyal, having no connection with the branchiostegals. Polymixia possesses the orbitosphenoid bone and is a true berycoid, while the Mullidæ are genuine percoid fishes.
Four species of Polymixia are recorded from rather deep water: Polymixia nobilis from Madeira, Polymixia lowei from the West Indies, Polymixia berndti from Hawaii, and Polymixia japonica from Japan. All are plainly colored, without red.