HEMIGLYPHIDODON 75 



This genus is separated from Abudefduf by its very numerous 

 and exceedingly long gill rakers, over 70 being present on the 

 first arch, a character which I consider of generic value. It has 

 a single series of flattened, more or less notched teeth, and 

 entire opercular and orbital bones in common with Abudefduf. 



Only one species is known and it is confined to the Indo-Aus- 

 tralasian Archipelago. 



HEMIGLYPHIDODON PLAGIOMETOPON (Bleeker) 



PLATE 5, FIG. 1 



Glyphisodon plagiometopon BLEEKER, Nat. Tijd. Ned. Ind. 3 (1852) 



67; GiiNTHER, Cat. Fishes 4 (1862) 51; BLEEKER, Nat. Verb. Holl. 



Maats. Wet. 2 (1877) 103; Atlas Ichth. 9 (1878) pi. 410, fig. 4. 

 Abudefduf melanopselion FOWLER, Proc. Acad. Nat. Sci. Phila. 70 



(1918) 59, fig. 23; FOWLER and BEAN, Proc. U. S. Nat. Mus. 62 



(1922) 49. 



Dorsal XIII, 12 or 13; anal ft, 13 to 15; scales in lateral 

 series 26 ; with tubules 15 to 18 ; between lateral line and origin 

 of dorsal 4 or 5 ; between lateral line and vent 10. 



Body oblong and deep, anterior profile oblique, slightly 

 arched; depth of body 1.9 to 2 in length; head 2.7 to 3.1; depth 

 of caudal peduncle 6.3 to 6.9. Interorbital space strongly con- 

 vex, rather wide, being 2.7 to 3.2 in head or a little narrower 

 than the length of the long, slightly pointed snout, which is con- 

 tained 2.4 to 2.9 in head; cleft of small mouth oblique, jaws 

 equal; maxillary 3.1 to 3.5 in head, its posterior end a little 

 behind nostrils; eye rounded, its diameter 3.3 to 4.1 in head; 

 teeth in a single series, with the tips truncate. Gill rakers very 

 long and numerous, 35 + 45 on first arch. Width of preor- 

 bital at angle of mouth about f eye diameter; orbitals and 

 preopercle with entire edges; opercle armed behind with a 

 flat spine. 



Head everywhere covered with scales excepting part of snout 

 in front of nostrils, orbital ring, and posterior edge of pre- 

 opercle; dorsal and anal fins with a low basal sheath of scales. 

 Dorsal spines increasing in height to behind. Soft dorsal and 

 anal slightly pointed; caudal obliquely truncated; pectoral ex- 

 tending to anus; ventrals reaching origin of anal fin, its two 

 outer rays about equal in length. 



Color in alcohol brown, with a bluish vertical streak on each 

 scale of body; a bluish curved line on suborbital, some bluish 

 dots on head and on base of vertical fins. All the fins dusky, 

 the pectoral somewhat paler than the rest and having a blackish 

 spot at base. 



