96. POMACENTKID2E POMACENTRUS. 609 



FAMILY XCVL POMACENTBID.E. 



(The Pomacentroids.} 



Labroid fishes with, the body short, deep, cbm pressed, covered with 

 ctenoid scales; lateral litie wanting posteriorly; mouth moderate, usu- 

 ally with rather strong teeth; vomer and palatines toothless; nostril 

 single on each side,* nearly round ; preopercle with its posterior edge 

 largely free; dorsal fin single, with the spinous portion longer than the 

 soft, which is similar to the soft anal; anal spines 2; ventral fins tho- 

 racic, I, 5, the anterior rays longest. Lower pharyngeals fully united; 

 branchiostegals 5-7; gills 3; slit behind the last gill very small or ob- 

 solete; no labyrinthiform appendage ; air-bladder and pseudobranehire 

 present; gill-membranes free from the isthmus. Vertebrae 12+14. 



Fishes of the tropical seas, similar in mode of life to the Chcctodontida\ 

 feeding on small marine animals and plants in the coral reefs. Genera 

 10 ; species about 160. 



(Pomaccntndae Giiuther, iv, 2-64.) 



a. Teeth incisor-like, fixed, in one series POMACENTUTS, 3-25. 



aa. Teeth conical, in 2 or more series CHHOMIS, 3*6. 



825. POMACENTRUS Lacepede, 

 Demoiselles. 



(Glyphidodon Lac.: Hypsypops, Pomalaprion, and EuscMstodus Gill.) 

 (Lac6pede, Hist. Nat. Poiss. iv, 50d, 1802: type Chwtodon pavo Bloch.) 



Body ovate, deep and compressed; the profile steep. Head moderate, 

 nearly as deep as long, almost everywhere scaly. Mouth quite small, 

 terminal ; the jaws equal; both jaws armed with a single series of com- 

 pressed teeth, notched or not, immovable. Gill-rakers long; preop- 

 ercle entire, or more or less serrate; preorbital serrate or entire. 

 Scales large, strongly ctenoid, the lateral line running parallel with 

 the back to near the end of the dorsal fin, at which point it ceases. 

 Dorsal fin continuous, with 12 or 13 low stout spines; the soft part 

 more or less elevated, its last rays gradually shortened; anal fin sim- 

 ilar to soft dorsal, with two spines, of which the second is much the 

 larger; dorsal spines with a sheath of large scales, the membranes of 

 both dorsal and anal covered high up with small scales; caudal fin 



*As in the Cichlidai. All other Acanthopteri have two nasal openings on each side. 

 Bull. Nat. Mus. No. 16 39 



