SIXTY-TWO SPECIES OP FISHES FROM LAKE ERIE 
345 
slightly and evenly to vent without constriction; marginal fin fold intact; pectorals 
larger but not rayed. 
Pigmentation. — The yolk is yellowish in color. Ventral chromatophores are 
now arranged in a double row of large stellate spots from before middle of yolk to 
vent, and are continued in a double row behind, much closer together. Many 
chromatophores occur over air bladder, and a row of 4 over last one-third of yolk 
sac. Over these last, and corresponding in position, there is a row of 5 chromato- 
phores on lateral line. Two chromatophores are apparent before each pectoral and 2 
behind. 
4 days old . — Total length, 6.0 millimeters. Body very deep with yolk sac almost 
if not entirely absorbed. Marginal fin fold intact, continued forward on the ventral 
side corresponding to the dorsal; pectorals very large. 
Pigmentation v — The eyes are metallic blue and black, and the cardiac region and 
blood stream are greenish yellow. Chromatophores grouped as before. 
1 weekold . — Total length, 6.0 ; length to vent, 3.75 ; greatest depth, 0.9 millimeter. 
Myomeres, about 21 to vent plus about 13 behind. Total length of larva not changed 
since the age of 4 days, but body assuming more 
advanced development and proportions; yolk 
absorbed; vent somewhat farther back and more 
myomeres developed forward. 
Pigmentation. — The pigmentation is gener- 
ally unchanged in this stage, but intensified, 
consisting of chromatophores sparsely distributed 
on top of head and anterior dorsal aspect, a few 
on sides of head, a series of large chromatophores 
rather far apart along lateral line from behind 
air bladder to end of body, and 1 large subsur- 
face spot at base of pectoral. The top of air 
bladder is very darkly pigmented, and 3 large 
round chromatophores follow the curve of gill 
arch below on each side of throat region. Behind 
and parallel with these, and before the air blad- 
der occur a double series of about 6 to 8 large stellate spots. On the under side, from 
middle of stomach region to vent, about 4 lines of similar chromatophores appear, 
followed by a conspicuous double series on ventral ridge to end of body. A few are 
evident on ventral part of caudal. 
2-weeks old . — Total length, 6.5; length to vent, 4.0; greatest depth 0.82; diameter 
of eye, 0.4 millimeter. Myomeres, about 21 before vent plus about 15 behind 
(incomplete). General shape and pigmentation unchanged, except that more color 
is evident. 
Pigmentation. — A yellowish tinge extends over top of head and along dorsal 
ridge to end of body. The top of stomach region is faint yellowish with numerous, 
small, raised yellow spots as though superimposed upon the heavy black chromato- 
phores of the air bladder. The eye is very iridescent with lavender, pink, blue, and 
yellow casts on a brilliant silver background. Over the air bladder a short region of 
iridescence similar to that of the eye is evident on a line with the median black chro- 
matophores running along top of intestine. This is apparently the beginning of the 
silvery adult condition. 
