138 
BULLETIN OF THE BUREAU OF FISHERIES 
KEY TO THE SPECIES 
a. Dorsal fin inserted over or in advance of origin of anal, with 10 to 15 rays; its base equal to or 
longer than that of the anal. 
b. Scales rather large, 33 to 38 in a lateral series. 
c. Body robust, average depth in length about 3.2; 11 to 13 oblique series of scales between 
upper angle of gill opening and origin of dorsal; ventral fins usually inserted equidistant 
from tip of snout and base of caudal; size rather large, maximum length about 125 
millimeters .... heteroclitus, p. 138 
cc. Body less robust, average depth in length about 4; 18 or 19 oblique series of scales between 
upper angle of gill opening and origin of dorsal; ventral fins usually inserted about an 
eye’s diameter nearer base of caudal than tip of snout. 
e. Snout rather long, 2.6 to 3.5 in head; dorsal fin with 13 to 15 rays; young of both sexes 
with vertical black bars along sides; adult males with vertical side bars and a black 
ocellus on posterior rays of the dorsal; adult females with longitudinal black stripes 
and with variable oblique and vertical bars; size large, maximum length about 200 
millimeters majalis, p. 140 
ee. Snout shorter, 3.7 to 5.5 in head; dorsal fin with 10 or 11 rays; both sexes usually 
with a black ocellus on the posterior rays of the dorsal; size rather small, maximum 
length about 65 millimeters ocellaris, p. 141 
bb. Scales rather small, 41 to 46 in a lateral series, 14 to 18 oblique rows between upper angle of 
gill opening and origin of dorsal; ventral fins inserted about an eye’s diameter nearer tip of 
snout than base of caudal; size medium, maximum length about 111 millimeters 
diaphanus p. 143 
aa. Dorsal fin inserted over or a little behind origin of anal, about equidistant from the tip of the tail 
and anterior half of eye, very small, with only 8 rays its base shorter than that of the anal; 
snout short, 4 to 4.8 in head; size small, maximum length about 50 millimeters lucise, p. 144 
59. Fundulus heteroclitus (Linnaeus). Mummichog; Mud minnow; Killifish; Common killifish; 
“Pike minnow”; “Mud dabbler”; “Gudgeon.” 
Cobitts heteroclita Linnaeus, Syst. Nat., ed. XII, 1766, p. 500; South Carolina. 
Fundulus viridescens Uhler and Lugger, 1876, ed. I, p. 147; ed. II, p. 126. 
Fundulus heteroclitus Uhler and Lugger, 1876, ed. I, p. 149, ed. II, p. 127; Bean, 1891, p. 92; Smith, 1892, p. 66, PI. XIX; Jordan 
and Evermann, 1896-1900, p. 640, PI. CII, fig. 273; Smith and Bean, 1899, p. 184; Evermann and Hildebrand, 1910, p. 159. 
Fundulus pisculentus Uhler and Lugger, 1876, ed. I, p. 149; ed. II, p. 127. 
Fundulus heteroclitus macrolepidotus Fowler, 1912, p. 54. 
Head 3.2 to 3.7; depth 2.8 to 3.7; D. 11 or 12; A. 10 to 12; scales 35 to 38. Body rather 
robust, compressed; caudal peduncle strongly compressed, its depth 1.65 to 2.1 in head; head 
depressed; snout short, broad, its length, 2.7 to 4.7 in head; eye 4 to 5.8; interorbital 2.1 to 2,3; 
mouth terminal, mostly transverse; premaxillaries protractile; teeth all pointed, in villiform bands, 
the outer ones somewhat enlarged; scales moderate, 11 to 13 oblique series between upper angle of 
opercle and origin of the dorsal; dorsal fin rather long, higher in adult males than in females, its 
origin slightly in advance of origin of anal, inserted nearer end of caudal than tip of snout in adult 
females, about equidistant from tip of snout and end of caudal in adult males; caudal fin broadly 
rounded; anal fin with a slightly shorter base than the dorsal but with longer rays, the oviduct 
attached to the first ray; ventral fins rather small, inserted about equidistant from tip of snout and 
base of caudal; pectoral fins rather broad, 1.3 to 1.6 in head. 
Color of large female in life plain brownish green above, paler underneath. Small females 
usually with 13 to 15 dark cross bars, narrower than the interspaces. No dark vertebral line; a 
small dark area at origin of dorsal; fins all unmarked, the vertical ones often with a greenish tinge. 
Color of a 3-inch breeding male dark green or olive above, blending into silvery on lower part of sides; 
yellow underneath; sides with about 15 narrow silvery vertical bars and numerous irregular white 
or yellowish spots, pale spots extending on lower half of vertical fins; head brownish between the 
eyes; silvery-blue punctulations below eyes; operculum dusky above, golden below, with punctula- 
tions; chin olive; caudal peduncle the color of back; dorsal and caudal dusky with yellow margins, 
a dark spot on posterior 4 or 5 rays of dorsal (this spot may not always be present) ; anal and ven- 
