BULLETIN FLORIDA STATE MUSEUM


lations of albeolus; peritoneum uniformly black; dorsal fin inserted
directly above pelvic; scales along anterior-lateral part of body much
taller than wide, becoming more pronounced with age; posterior edges
of scales along side of body smooth and without scallops; nuptial
tubercles well developed, the tips usually straight, sometimes curved
forward; tubercles present in a single row along lower jaw, absent
from tip of chin, present over entire head and along back as far as,
and including, anterior part of dorsal fin; tubercles normally present
only in breeding males (weakly developed in females of N. cerasinus);
crescentic vertical streaks usually well developed along side of body,
but either absent or weakly developed in N. albeolus; no red bar pres-
ent on cheek or on margin of opercle and preopercle; caudal spot ab-
sent; no consistent pattern of dark pigmentation present in either the
dorsal or caudal fins; circumferential scales usually 12 to 17-2-11 to
15; caudal peduncle scales usually 7-2-7 (7-2-5 or 6 in N. cerasinus);
a black lateral stripe sometimes present on body of young but not
consistently present throughout life.
 The three species groups do not seem extremely close to one an-
other. Their morphological differences are fairly sharp, and no con-
necting links exist between them. The relationships within each
group, on the other hand, appear generally quite close, particularly
in the zonatus and, to a lesser extent, the coccogenis groups. With
one exception this holds true for the cornutus group also. N. cerasi-
nus, although obviously much more closely related to N. cornutus and
N. chrysocephalus than to any of the other species of Luxilus, differs
notably from them in the character of the nuptial tubercles and their
normal presence in females, in the slight difference in appearance of
the scales, and in the number of caudal peduncle scales.
 The closest relatives of Luxilus are those species of Notropis that
 share with it the largest number of similar or identical morphological
 characters. To base a relationship on only one or two shared features
 can be misleading. Some of the most constant diagnostic characters
 in the forms of Luxilus-pharyngeal tooth counts, anal ray counts,
 color of peritoneum, shape of scales along side of body, size of eye,
 and relative position of dorsal and anal fins-vary considerably among
 other closely related Notropis species.
 Notropis ariommus seems rather close to the subgenus Luxilus.
 This species has in common with Luxilus: 2,4-4,2 teeth, a black peri-
 toneum, large eye, dorsal fin inserted slightly posterior to the pelvics,
 and crooked parallel stripes running along the upper side of the back.
 In addition ariommus lives under ecological conditions quite similar
 to those preferred by all forms of Luxilus, particularly N. zonatus and


Vol. 8