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BULLETIN OP THE BUREAU OF FISHERIES 
the typical dark chromatophore marking seen on the ventro-lateral aspect of the 
newly hatched larva, and the small black pigment spots extend far out over the yolk. 
The incubation of muskalonge eggs requires approximately 12 to 20 days, and the 
yolk is absorbed in about 12 days after hatching. 
11.6-millimeter stage . — Total length, 11.6; length to vent, 8.5; length of head, 
1.65; snout, 0.15; diameter of eye, 0.58; greatest depth before vent, 1.95; depth 
behind vent, 1.55 millimeters. Myomeres, 45 to vent plus about 21+ behind. 
Marginal fin fold intact from shortly behind head around lophocercal caudal and 
forward ventrally to yolk sac, with little elevation. Pectorals developed but small. 
Vent situated at some distance from body, at edge of marginal fin, and very evidently 
marked by the dark pigmentation of intestine. A large reddish yolk sac with many 
rather small, clear oil globules present. 
Pigmentation. — The dark median band so characteristic of later stages is evident 
now, beginning behind eye and running over yolk sac into ventro-lateral aspect of 
body, which region is closely and darkly pigmented below lateral line from yolk sac 
almost to tip of tail. Dorsal half of body has chromatophores sparsely distributed 
before vent but more numerous behind, extending out on marginal fin fold above and 
below in caudal region. The eye is darkly pigmented. Many stellate chromato- 
phores occur over top of yolk sac. 
Figure 71 . — Esox masquinongy, 13.9 millimeters 
13.9-millimeter stage . — Total length, 13.9; length to vent, 9.4; length of head, 
2.7; snout, 0.55; diameter of eye, 0.73; greatest depth before vent, 1.65; depth behind 
vent, 1.8 millimeters. Myomeres, 45 to vent plus 23 behind. Marginal fin reduced, 
especially dorsally anterior to vent; pectorals larger but unrayed; notochord straight. 
Although the yolk is not entirely absorbed in this stage, radical changes are occurring 
in the development of head. Snout longer, and profile behind tip of upper jaw 
slightly concave to its highest point at anterior margin of eye; lower jaw projecting; 
maxillary to just beyond anterior margin of eye. Vent still at ventral margin of 
embryonic fin fold. A few globules on ventral aspect constitute the only remaining 
oil in the yolk. 
Pigmentation. — Chromatophore grouping is essentially as in the 11.6-millimeter 
stage. The lateral pigment band now starts at tip of jaws, and extends below the 
surface over cheeks. The chromatophores through the body region are arranged 
more in oblique series covering each myomere. 
