FAMILY PERCIDA. 35 
GENUS APHREDODERUS.  Lesueur. 
Six branchial rays. Teeth velvet-like. Denticulations on the two edges of the suborbital. 
Preopercle denticulated. Opercle with a spine at its angle. Ventral fins without a spi- 
nous ray. Vent under the throat. 
’ 
Ozs. This genus is founded on a species first observed in the neighborhood of Philadelphia, 
and referred, after a very slight examination, to Scolopsides of Cuvier, a genus of the family 
Scienide. The presence of teeth on the palatines excludes it, however, from this family. 
Subsequently Lesueur again saw it at New-Orleans, and elaborated its characters under a 
new genus Aphredoderus of the family Percide. This genus is in fact one of the most sin- 
gular of the whole family, by the position of its vent, and the absence of a spine to the ventral 
fin. But one species has yet been detected. 
THE SPINELESS PERCH. 
APHREDODERUS SAYANUS. 
PLATE XXL FIG. 62. 
Scolopsis sayanus. G1Lutams, Jour. Acad. Nat. Sc. Vol. 4, p. 81, pl. 3. 
Aphredoderus gibbosus. Cuv. et Vat. Hist. Poiss. Vol. 9, p. 448, pl. 278. 
Characteristics. Dusky ; beneath light yellowish. Gibbous. Length three to five inches. 
Description. Body oblong, thick, subcompressed. Back elevated, descending with an equal 
curve from the soft rays of the dorsal to the nape. Depth to total length as one to four nearly. 
Scales small, rough, rounded and ciliated ; forty-five to fifty are counted in a longitudinal series. 
The lateral line very slightly curved, nearly straight, and passing near the middle of the body. 
Head flattened above. The anterior portion of the suborbital has a bony crest, supporting 
two or three spines, which are continuous with the denticulated crest of the upper margin, so 
that the lower margin of the orbit is smooth, while the upper two-thirds of the margin is rough ; 
two crests form a longitudinal furrow between them. Preopercle wide, finely denticulated> 
with its angle rounded, and covered with six rows of scales. Opercles large, scaly, with a 
smooth margin, but a short robust spine near its angle. Eyes moderately large. Nostrils 
double ; that near the margin of the orbit large, with an anterior valvular membrane ; the 
anterior somewhat smaller, tubular. Lower jaw longest. Numerous conic incurved teeth on 
the jaws, anterior part of the vomer, palatines and pharyngeals. ‘Tongue smooth ; its end 
rounded and free. Branchial rays six. At the angle formed by the fold of the branchial 
membrane, is placed the vent. 
Dorsal fin high, commencing an inch and a half from the end of the snout, and placed in 
the middle third of its body ; it has three, and according to Gilliams four, spinous rays ; the 
branched rays higher than the others, nearly subequal, the last somewhat shorter. Ventrals 
