96 U.S. NATIONAL MUSEUM BULLETIN 2 02 Vol. 2 



edge of gill opening to base of caudal rays 27 to 30 (usually 29), with 

 4K between lateral line and origin of dorsal fin, 11 or 12 between lateral 

 line and origin of anal; upper part of lateral line with 21 or 22 tubular 

 scales; gill rakers 2 or 3 + 1 + 11, totaling 14 or 15 (4 counts.). 



Depth of body 1.7 to 1.8; length of head 2.9 to 3.7; both in standard 

 length. Snout 3.2 to 3.7; eye 3.1 to 3.8; preorbital width 5.7 to 6.9; 

 length of upper jaw 3.7 to 3.9; postorbital part of head (hind margin 

 of eye to upper edge of gill opening) 2.6 to 2.8; interorbital width 2.9 

 to 3.2; depth of caudal peduncle 1.9 to 2.1; length of pectoral fin 

 1.1 to 1.2, of pelvic fin 1.1 to 1.2, of 13th dorsal spine 1.6 to 1.9, of 

 upper caudal rays 1.0 to 1.1, of lower caudal rays 1.0 to 1.1; all in 

 length of head (tip of snout to posterior margin of opercular mem- 

 brane); depth of caudal peduncle in its length 0.7 to 1.0; angle of 

 snout profile with lengthwise axis of body 53 degrees. 



Teeth of jaw uniscrial, long, slender, curved, blunt-pointed or 

 rounded, scales extending forward on snout to beyond nostrils; 

 preorbitals only partially scaled, suborbitals scaled; preopercular 

 margins scaled, scales on opercle extending beyond opercular margin 

 to posterior edge of opercular flap, which is narrow, opercular spine 

 not evident; lips thick, plicate, finely fimbriate; dorsal spines gradu- 

 ally increasing in length to last; soft dorsal and anal rounded in 

 young, angular or pointed in largest specimens; caudal lobes angular; 

 pelvics pointed; pectoral angular. 



Color in alcohol. — Head and body purplish brown, lower parts 

 somewhat paler, upper fins all dusky in largest specimen (77 mm.); 

 medium sized individuals (50 to 65 mm.) with narrow dark vertical 

 lines along scale bases, appearing as a cross-hatching upon a light 

 yellow background; top of head and back dark brown or blackish; 

 fins all blackish, except pectoral which is dusky, usually an indistinct 

 dark brown blotch across posterior part of body just anterior to 

 caudal peduncle or posterior part of body from insertion of anterior 

 dorsal and anal soft rays; caudal posterior to end of scaly portion 

 blackish; smaller specimens (40 to 50 mm.) may have posterior part 

 of body pale yellowish, or with a very distinct dark blotch smaller 

 than described above; in these specimens the dorsal fin is dusky 

 blackish and the rest of the fins completely pale or with dark edging. 

 Backs of post-larvae (21 mm.) brownish with large black spot under 

 the soft dorsal base, underparts silvery, spiny dorsal black-edged, a 

 trace of dusky coloring on distal portion of upper pectoral rays, 

 remaining fins pale. 



Ecology. — The post larvae, 21 mm. in standard length, are pelagic. 



Remarks. — Fowler and Ball have made this species the type of a 

 separate genus, Plectroglyphidodon, "distinguished from Abudefduf by 

 the plaited lips." It is true that the lips are thick, ridged, and 



