GILBERT: FISHES OF THE SUBGENUS LUXILUS


running along dorso-lateral part of back; red and black pigment not
especially pronounced in breeding specimens.
 DESCRIPTION. Counts and measurements are given in tables 5 and
9 through 15. All distinctive pigmentary characters of the species
are analyzed in table 2 and are shown in figure 5B. Characters men-
tioned in the above diagnosis are not repeated in the following para-
graph:
 Body slender and terete at all sizes; anterior dorso-lateral scales
(14) 15 to 17 (18); circumferential scales (24) 25 to 29 (30): sum of
anterior dorso-lateral and circumferential scales (39) 41 to 45 (48);
an olive area about 21/z times as wide as mid-dorsal stripe (not so
sharply defined as in N. cornutus) extending along body on either side
of mid-dorsal stripe; side of body silvery, with a dusky-black stripe
running from snout to end of caudal peduncle, this stripe often over-
lain with a plumbeous coloration which disappears in preservative;
mid-dorsal stripe black, slightly more than half as wide as eye, and
extending around base of dorsal fin; breast, belly, and lower side of
head silvery, becoming reddish in breeding males; back olivaceous;
lips, preopercular bar, and pectoral axil reddish in breeding males;
top of head dark gray to black; branchiostegals ordinarily colorless,
becoming reddish in breeding males except for gray borders; nuptial
tubercles weakly developed, granular in all but highest breeding
males in which they project slightly; four or five tubercles present
in single row on lower jaw and absent from chin; tubercles present
on snout and upper part of head, but apparently absent from pre-
dorsal area of back and dorsal fin.
 DISTRIBUTION, In the White River system (excluding the Black
River) in Arkansas and Missouri and in a few tributaries of the Ar-
kansas and Red rivers in Arkansas, Kansas, and Oklahoma.
 N. pilsbryi probably is the most abundant cyprinid in the White
River system, particularly in clear, upland tributaries. It is also
common in many streams draining into the Illinois and Neosho rivers,
tributaries of the Arkansas, although it seems rather scarce in some
parts of the Neosho system. It is found in the lower reaches of the
Illinois River and has been reported from the Arkansas River itself
(Hubbs and Moore, 1940: 94). Its presence in the Red River system
has been suggested by Hubbs and Moore (1940: 94) to be due to in-
troduction, but its occurrence in three widely separated localities in
this drainage suggests natural distribution.
 LIFE HISTORY AND ECOLOGY. Notropis pilsbryi occupies the same
type of habitat as the closely related N. zonatus. Its occurrence in


1964