behind 4th. Pseudobranchiae very large. A single dorsal fin, not notched, spinous portion rather longer than soft. Anal spines 3. Ventrals thoracic, with a spine and 5 rays, without axillary process, inner ray joined to abdomen by membrane. Airbladder large. Pyloric caeca few. Lateral line single. A small family of carnivorous fishes from tropical and subtropical seas, chiefly from deep water. Its external distinguishing features are the peculiar scales (text-fig. 20) and the large pseudobranchiae. Osteologically it is characterised by the abbreviation of the posterior part of the skull and a reduction in the number of vertebrae. FIG. 20.-Scale of Priacanthus arenatus. Gen. PRIACANTHUS Cuv. 1817. Cuvier, Règne Anim., vol. ii, p. 281. Scales very small, 70-120 in longitudinal rows. Dorsal spines increasing in length posteriorly. None of the spines in the fins very strong, often spinulose and roughened or feebly striate. Preopercle with a more or less developed spine, without a submarginal row of denticles. Key to the South African species. 1. Tenth dorsal spine not more than twice as long as 2nd. a. Dorsal soft rays 12-13, anal 13-14 b. Dorsal and anal rays 14-15. 2. Tenth dorsal spine more than twice as long as 2nd Priacanthus cruentatus (Lacép.). Big-eye. cruentatus. hamrur. boops. 1802. Lacépède, Hist. Nat. Poiss., vol. iii, p. 522, pl. ii, fig. 3. 1876. Bleeker, Atl. Ichthyol., vol. vii, p. 13, pl. cccli, fig. 5 (carolinus). 1878-88. Day, Fish. India, p. 48, pl. viii, fig. 2 (blochii). 1905. Jordan and Evermann, Bull. U.S. Fish. Comm., vol. xxiii, p. 229, fig. 94. 1917. Gilchrist and Thompson, Ann. Durban Mus., vol. i, pt. 4, p. 337 (references and synonymy). |