SIXTY-TWO SPECIES OF FISHES FROM LAKE ERIE 
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and ventral extremities of body. Almost no chromatophores appear on ventral 
aspect. The peritoneum is dark. All fins except ventrals have many chromato- 
phores, those of the dorsal giving a checked appearance. The brilliant indigo-blue, 
orange, and crimson of the male are not indicated in these young specimens. 
46. Poecilichthys exilis (Girard). Iowa darter. [Boleichthys exilis Girard 
Jordan, Evermann, Clark, p. 294.] 
RECORD OF CAPTURE 
The Iowa darter is restricted in its distribution to certain sheltered bays along 
the Lake shore and several of the larger tributaries. 
DESCRIPTION 
This darter is distinguished from the rainbow darter by fewer rays in the soft 
dorsal, more slender body, and the bars confined to middle of sides. 
19. 5 - millimeter stage. — Total length, 19.5; standard length, 16.25; length to vent, 
10.0; length of head, 5.0; diameter of eye, 1.5; greatest depth, 2.75 millimeters. 
Myomeres, 21 to vent plus 19 behind. Dorsal IX, 11; anal II, 7; ventrals close 
together; caudal squarish. Lateral line incomplete; snout only moderately decurved. 
Pigmentation. — Chromatophores are thickly distributed over both jaws, back of 
head, in 3 to 5 longitudinal rows on dorsal surface to tip of tail (with slight breaks in 
5 places), on opercles and preopercles, in 12 clusters along lateral line from head to 
caudal, speckling whole body, especially dorsally, in single fine from vent to tail, in 
heavy subsurface patches over stomach region and on all fins. 
47. Catonotus flabellaris (Rafinesque). Fan- tailed darter. 
RECORD OF CAPTURE 
This darter is common in the Lake Erie region but is limited to the streams, 
frequenting the headwaters and never venturing into the open lake. 
DESCRIPTION 
The fan-tailed darter is similar to Poecilichthys, but differs primarily in its pro- 
jecting lower jaw and scaleless head. 
22.6- millimeter stage. — Total length, 22.6; standard length, 19.5; length to vent, 
11.5; length of head, 6.0; diameter of eye, 1.5; greatest depth, 3.75 millimeters. 
Dorsal VIII, 12 (very low); anal II, 8; caudal large and rounded; ventrals close 
together. Body slender and compressed ; head long ; very oblique, lower j aw definitely 
protruding; premaxillaries not protractile. 
Pigmentation. — Chromatophores are sparsely distributed on both jaws and 
front of head, and more heavily on brain region. A very pronounced longitudinal 
band extends from tip of snout through eye to back of head. Over the dorsal aspect 
about 10 darker patches are apparent. Chromatophores occur also on surface and 
below surface in opercular region, in about 10 patches on lateral line forming short 
horizontal bars and over all lateral surface, sometimes irregular, or in criss-cross 
pattern. Ventral aspect is clear to vent, thence chromatophores border anal fin and 
those of lateral pattern on either side meet behind. All fins except ventrals are 
pigmented. 
