SIXTY-TWO SPECIES OF FISHES FROM LAKE ERIE 
313 
Pigmentation. — There is still much yellow over yolk region, and whole head is 
tinged with yellow. Number and arrangement of chromatophores is as in 12- 
millimeter specimen described above, but the size of all chromatophores is increased 
until they overlap in marginal series. 
18. 5 -millimeter stage . — Age unknown but similar to specimens 61 days old. Total 
length, 18.5; standard length, 17.0; length to vent, 13.25; length of head, 4.0; depth 
of head, 2.25; greatest depth behind head, 2.0; diameter of eye, 1.6 millimeters. 
Dorsal rays fairly well developed; embryonic marginal fin fold starting again after 
wide space behind dorsal, continuing to caudal, complete on ventral side, with basal 
elements of anal fin developed but no rays; caudal slightly notched dorsally at end 
of notochord, lower portion becoming forked and rays well formed ; ventrals prominent. 
Pigmentation. — Dorsal and ventral series of chromatophores are still prominent, 
but many smaller ones have become scattered over sides of head, body and caudal. 
22.0-millimeter stage . — 65 days old. All fins fully developed with exception of 
adipose, in which region a large fragment of the embryonic fin fold remains. 
31 .5 -millimeter stage . — Age unknown but similar to specimens 95 to 109 days 
old. Total length, 31.5; standard length, 27.0; length of head, 6.75; greatest depth of 
body, 4.5; diameter of eye, 2.0 millimeters. Assuming shape of adult. 
Pigmentation. — The chromatophores are essentially as in younger specimens 
but they have become more diffused, with dorsal and ventral ridges of body from head 
to caudal still most deeply pigmented. Black, stellate, dorsal chromatophores con- 
tinue down the sides of body to lateral line, becoming gradually smaller and wider 
apart. The lateral line is marked by closely distributed small black spots. A few 
chromatophores appear on ventral aspect of stomach; none beneath the intestine. 
The large areas of chromatophores behind eye are still noticeable, and many more, 
lighter in color, show between and before the eyes, becoming darker at mouth. Dorsal 
and caudal are speckled with black, following lines of rays. The body, and especially 
the head, are silvery at this stage. 
