SIXTY-TWO SPECIES OF FISHES FROM LAKE ERIE 
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vent ending far from body at edge of marginal fin. Pectorals considerably larger; 
dorsal embryonic marginal fin fold raised somewhat before the vent, dropping again 
about midway from vent to end of myomeres; ventral marginal similarly elevated just 
behind the vent; caudal lophocercal. 
Pigmentation. — Chromatophores occur on underside of yolk in a very irregular 
double row, fewer and smaller than in the preceding stage. There is a single row of 
Figure 85. — Perea flavescens, 7.3 millimeters 
about 15 very tiny ones on ventral aspect behind vent, and, extending upward from 
it a short way over the sides, are a series of from 1 to 3 small chromatophores between 
each myomere. Two chromatophores appear on intestine at vent. 
8.25-millimeter stage . — Yolk completely absorbed, and simple intestine evident. 
Fins and chromatophores as before. 
9.0-millimeter stage . — Total length, 9.0; length to vent, 5.0; greatest depth, 1.04; 
diameter of eye, 0.5 millimeter. This and successive stages changing mostly in 
Figure 86. — Perea flavescens, 9 millimeters 
development of head and heavier body. Pigmentation remains the same, consisting 
of a single ventral series from vent backward, and an irregular line on either side of 
body midway between ventral ridge and lateral line. 
12. 5 -millimeter stage . — Total length, 12.5; standard length, 12.0; length to vent, 
6.2; greatest depth, 2.1; diameter of eye, 0.6 millimeter. Stomach region prominent 
showing coiled intestine; head more pointed. Marginal fin fold intact but dorsal 
portion elevated and small elements of 7 rays starting immediately above vent, one 
Figure 87. — Perea flavescens, 12.5 millimeters 
for each myomere; in other specimens of this length, a cell concentration indicating 
later location of anal; few rays on ventral part of caudal but still lophocercal; pectorals 
moderate. 
Pigmentation. — A few chromatophores are developed around both jaws and top 
of head, a few on preopercle, a subsurface group over stomach region, and 1 very large 
chromatophore on ventral aspect midway to vent. The lateral and ventral series of 
17 to 25 are about as before. 
