IG POMAQE^rTRIPiE. 



5. POMACENTRUS *. 



Pomacentrus, (Lacdp.) Ciiv. (^ Vnl. v. p. 412. 

 Pristotis, Elipp. N. TV. Fisckc, p. 128. 



Prfeopereiilum and, generally, the infraorbital ring serrated ; oper- 

 culum with one or two small spines. Teeth small, compressed, with 

 the crown entire or slightly emarginate, in a single series. Dorsal fin 

 with twelve or thirteen spines, anal with two. Scales of moderate 

 size, in less than thirty transverse series ; the lateral line ceases below 

 the soft dorsal fin. Branchiostegals five; gills three and a half ; pseudo- 

 branchia? present ; an air-bladder. Pyloric appendages three. 



Tropical seas of both hemispheres ; more abundant in the Indian 

 Seas and in Polynesia. 



One of the characters mentioned, viz. the serrature of the praj- 

 operculum and praeorbital, is subject to variation according to the 

 age of the individual. The serrature, especially of the praeorbital, 

 is less distinct or entirely absent in young individuals of a species 

 which has that bone strongly denticulated in the mature state ; in 

 other species the prfeorbital does not appear to be serrated in any 

 stage of development. A similar change extends also to the prae- 

 operculum in some species; and such young individuals as show 

 neither the praeorbital nor the praeoperciilum serrated may be easily 

 mistaken for Glyi^hidodonts. If we consider moreover that the colours 

 also are subject to variation, we may well be cautious in describing 

 new species of these two genera. The British Museum possesses a 

 number of such young specimens, which we are unable to refer to any 

 known species. Several of the species established by Cuvier and 

 enumerated in the following list are apparently fomided on young 

 individuals, and \nll prove to be identical with others. 



Synojjsis of the Species. 



A. Body with broad cross-bands, or with large blotches across the back. 

 a. Those markings are pennanent in every age, p. 17. 



1. P. robustiis. 4. P. bifasciatus. 6. P. fasciatus. 



2. P. annulatus. 5. P. albofasciatus. 7. P. ti-imaculatus. 



3. P. nematoptenis. 8. P. chrysopcecilus. 



h. Those markings disappear in mature age, p. 20. 

 9. P. notophthalmus. 



B. Body uniform, or with small dots or fine and short streaks. 



a. The height of the body is one-third or less than one-third of the total 

 length. 



* 1. Pomacentrus emarginatus, Cuv. Sf Val. v. p. 422; Less. Toy. Coqu. Zool. 

 Poiss. p. 189. pi. 28. fig. 1.— Waigiou. 



2. brachialis, Cuv. 4' Val. v. p. 420. — Java. 



3. pietus, Casteln. I. c. pi. 2. fig. 1.— Brazil. 



4. at-er (Pomacentre noir), Lienard, Dixihne Rapp. Soc. Hist. Nat. 



Maurif. p. .34.— Mauritius. 

 5- atrocyaneus, Poey, Mem. Cub. ii. p. 190.— Cuba. 



