Jordan and Kvcrmann. Fishes of North America. 



510. DIPLECTRUM, Holbrook. 

 (SQUIRREL-FISHES.) 



,, HOLBROOK, Ichthyology of South Carolina, Ed. 1, 32, 1850, (j.wicnlm-ix 

 /////)(</, GILL, Proc. Ac. Nat. Sri. I'hihi., 1802, 230, (biviltatus =--- radial ix, and other species; 



restrict-, d to biriltatns by JORDAN & GILBERT, Synopsis, 535). 

 /'.mix IY.O/MS, BLKEKEU, Verh. Akad. Amst., xiv, 1873, 6, (hasselti). 



This genus is very close to Prionodes, from which it differs chiefly in 

 the armature of the preopercle, which is provided in the adult with 1 

 or 2 clusters of strong, straight, divergent spines. Smooth area on top 

 of head, as in Serranus, large, extending backward to a line connecting 

 borders of preopercle; the supraoccipital and parietal crests very short; 

 preorbilal broad ; maxillary widest before its tip ; profile of snout rounded ; 

 pectoral unsymmetrically rounded, its upper rays longest; ventrals 

 inserted* somewhat before axil of pectoral; dorsal spines slender, none 

 of them much elevated ; soft dorsal short, the rays X, 12 ; anal rays III, 7 ; 

 caudal lunate. Species all American, of small size and bright colors. 

 ((U'Cjtwo; TT^TfKrpov, spur.) 



HALIPERCA (aAs, sea; irepur), perch): 



a. Preopercle with a siuglo center of divergence of the spinules about its angle (in the adult 



as well as in the young). 



b. Gill rakers very long, slender, and numerous, about 25 below angle of arch; scales on 



cheek in 7 or 8 rows; preopcrcnlar process narrow and truncate, its width about % 

 head; no black within gill cover; a pale-blue streak below orbit; about 18 scales 

 before dorsal; head with opercular flap about 3 in body. SCIURUS, 1590. 



bb. Gill rakers moderate, about 10 below angle of arch; spines on produced portion of pre- 

 opercle numerous, 8 to 20 in number; outline of the spinous dorsal fin somewhat con- 

 vex, so that the fin is more deeply notched than in Diplectrum formosum; jaws equal; 

 vertex naked; operclo black within. 



c. Scales on cheeks small and regularly placed, in about 10 rows; 22 scales before dorsal; 

 head short, with opercular flap about 3 in body; width of preopercular process 4% 

 to 5 in head, its posterior edge rounded; gill rakers x + 10, ghort and slender, 

 well separated; region above the large eye prominent; snout short, bluntish; 

 cheeks with 10 rows of scales; these regularly placed; seme on preopercle much 

 produced in the adult, short in the young; upper lobe of caudal little produced. 

 Color light brown above, dull yellowish below; the scales on sides each with a 

 silvery center; irregular, vague, dark cross bars, broader than the interspaces; a 

 black bar at bafe of caudal; usually no blue lines or white areas on head; soft 

 dorsal with bright-blue spots, each surrounded by a dark-blue ring; caudal with 

 bars of similar spots; young with 2 black longitudinal stripes, the lower forming 

 a spot at base of caudal. RADIALE, 1591. 



cc. Scales on cheek large, irregular, in 5 or G rows; head larger; soft dorsal pale below, 



mottled above, without distinct blue spots; 15 to 17 scales before dorsal. 

 d. IK- ad moderate, 2% in total length, with opercular flap; width of preopercular pro- 

 cess 14 head, its posterior edge truncated; upper edge of preopercle nearer tip of 

 opercular flap than snout; brownish, with numerous traces of vague, dark cross 

 bars; a very distinct black caudal spot; snout with 4 or 5 pale blotches; a palo 

 streak from below eye across preopercular angle; no black at base of soft dorsal, 

 the fin with very faint traces of blue spots. MACROPOMA, 1592. 



dd. Head very large, 2% to 2% in total length (with opercular flap); upper angle of 

 preopercle midway between tip of snout and tip of opercular flap; preopercu- 

 lar process very broad; soft dorsal dark at base. Eritvri.KCTKr.M, 1593. 



* Essentially as in Centropristes, not as in Serranus, in which these species are placed by Dr. 

 Boulengcr. 



