85. PERCID.E — PERCA. 
523 
small, sliglitly oblique, maxillary reacbiug front of eye. Eye small, 4 
iu head. Cheeks and opercles with large scales. Opercular spine well 
developed. Scales large, the tubes of the lateral line developed on two 
of them 5 dorsals well separated. Anal spines slender, high; pectorals 
and ventrals reaching about to vent. Olive, speckled with brown ; ten 
brownish spots along the sides; black streaks downward and forward 
from eye; dorsal fins mottled. Head 4; depth 4^. D. VIll, 11; A. 
11, C. Lat. 1. 36. L. 1^ inches. Alabama and Mississippi. 
(Hay, Proc. U. S. Nat. Mus. 1880, 496.) 
825. M. piiEJCtuIafa Putnam . — Least Darter. 
Body rather short and deep, somewhat compressed, the back arched. 
Caudal peduncle rather long. Head moderate. The snout somewhat 
decurved. The mouth moderate, terminal, oblique. Cheeks naked. 
Opercles somewhat scaly. Opercular spine very small. Neck and chest 
naked. No trace of lateral line. The usual series of tubes along the tem- 
poral region. Scales quite large, strongly ctenoid. Vertical fins short. 
Anal spines strong, the first usually the largest. Coloration olivaceous, 
the sides closely speckled and with vague bars and zigzag markings ; sec- 
ond dorsal and caudal barred ; dark streaks radiating from eye; a dark 
humeral spot. Head 3^; depth 4J. D. Vl-Vll, 10; A. 11, G; Lat. 1. 
34. L. inches. Smallest of the darters, and one of the smallest of 
fishes, abounding in the clear streams of the Northwestern States. 
(Putuam, Bull. Mus. Comp. Zool. i, 1863, 4; Jordan, Man. Vert. 229.) 
2G8. — PEKCA Linnaeus. 
Perch. 
(Artedi: Linnaeus, Systema Naturae: type Perea jluviatilis Jj.) 
Body oblong,- somewhat compressed, the back elevated. Cheeks 
scaly ; opercles mostly naked ; the operculum armed with a single 
spine. Preopercle and shoulder girdle serrated. Mouth moderate, 
terminal ; premaxillaries protractile ; teeth in villiform bands on jaws, 
vomer, and palatines ; no canine teeth. Branchiostegals 7. Gill-mem- 
branes separate; pseudobranchiae small, but perfect; no anal papilla. 
Scales rather small, strongly ctenoid. Lateral line comi^lete. Dorsal 
fins entirely separate, the first of 12-15 spines; anal fin with two slender 
spines ; caudal emarginate ; air-bladder present. Pyloric coeca 3 ; ver- 
tebrae [P. jluviatilis) 21-f 20. Fresh waters of northern regions; three 
species now known: P. jluviatilis in Europe, P. sclirencld iu Asia, and 
P. americana. This genus has long been considered the tyj)e of the 
