PISCES. 169 



Mus. Ad. Frid. Tab. 33, fig. 6. This species lives in the Bed Sea and 

 in the Indian Ocean, like Platax teira Cuv., Chcetodon teira BLOCH 1. 1. 

 fig. i, with which BLEEKEB unites Platax vespertilio japonicus SCHLEG. 

 Faun. Japan., Pise. Tab. 43. The length of the dorsal and anal fins can- 

 not supply a character, since these fins in old individuals become obtuse 

 and rounded. See P. BLEEKER in the Verh. van het Batav. Genootechap 

 xxni. Deel, 1850. 



Platax arthriticus Cuv., Chcetodon arthriticus W. BELL, PhUos. Transact. 

 for 1793, PI. 6; Sumatra, Java. The skull is remarkable from a thick, 

 high crest; many of the spinous processes and interspinal bones have 

 tubercles or soft bony swellings. This species attains a very conspicuous 

 size. 



Amongst the fossil fishes of Monte Bolca, with many other squami- 

 pennes, species also of this genus occur, as Platax altissimus AGASS., 

 Poiss.foss. IV. PI. 41. 



Chcetodon L. (excl. of some species 1 ). Body oval, often high. 

 Teetli in jaws setaceous, crowded. Gape of mouth small. Ventral 

 fins distinct. Palate edentulous. 



Rock-fish. These fishes, mostly very beautifully coloured, of the 

 tropical seas, are very numerous. The form is various, and in this 

 respect even the species of the sub-genera or smaller groups differ 

 from each other, so that there are transitions from the one form to 

 the other. Four principal groups may be distinguished, round each 

 of which other smaller sub-genera arrange themselves. 



a) Prceoperculum armed at the lower part with a large spine directed 

 backivards. 



Holacanthus LAC. (and Pomacanthus ejusd.). Dorsal fin single, 

 caudal fin mostly rounded. 



Sp. Chcetodon armatus L., Mus. Ad. Frid. Tab. 33, fig. 5, BLOCH Ichth. Tab. 

 20 1, fig. 2; this and some other species with a very high body, and in 

 that case without spinous rays in the dorsal fin (Pomacanthus Cuv.), are 

 from South America. Others have an oval body, with a great number of 

 spinous rays in the dorsal fin (13 15), and the praeoperculum with a margin 

 usually toothed (ffolacanthus Cuv.). Of this division species are found in 

 both hemispheres; ex. gr. in the gulph of Mexico : Chcetodon ciliaris L., 

 Mus. Ad. Frid. Tab. 33, fig. i, BLOCH Ichth. Tab. 214, GUBRIN Iconogr., 

 Poiss. PL 23, fig. i ; Chcetodon nicobarcensis BL., SCHN., Holacanthus geo- 

 metricus LACEP., Cuv., BLOCH Syst. Ichth. Tab. 50 (a small elegantly 

 marked species), and Chcetodon imperator BLOCH Ichth. Tab. 194, Encycl. 

 Meth., Poiss. PL 93, fig. 284, are on the other hand from the E. Indies. 



1 Compare above, Dascyllus, p. 132, Acanthurus, p. 139; Chcetodon saxatUis L. 

 and Ch. rotundus L. belong to the genus Glyphisodon LAC., p. 132. 





