Biological Survey — Erie-Niagara Watershed 



87 



brown cliromatophores on both dorsal and ventral aspects; yolk 

 sac also pigmented posteriorly, near the body. Other eggs in col- 

 lection not yet hatched at 131 days. 



Fig. 13. — Coregonus clupeaformis less than 1 week old, 12 millimeters 



12.0 mm. stage. Fig. 13. Less than 1 week old. Total length 

 12.0 mm; length to vent 7.0 mm; greatest depth behind yolk sac 

 1.1 mm; diameter of eye 0.8 mm. Characterized by large, very 

 yellow yolk sac, and much yellow diffused in subsurface streaks 

 about the head, above the stomach, and in some specimens over 

 the whole body, thus differentiating it from Leiicichthys artedi in 

 which this color is less intense and limited to the yolk sac. Body 

 much heavier, the greatest depth behind yolk sac being 10.9 in 

 total length, while in a herring of equal development it is 12. 

 Embryonic marginal fin resembling herring, originating over 

 middle of yolk sac, notching somewhat about 11 myomeres before 

 the vent, rising again to highest point over vent, notching on 

 either side of peduncle, and breaking entirely at vent. Pigmenta- 

 tion essentially as the herring, but chromatophores generally much 

 larger, darker, more regularly arranged, consisting of few large 

 black stellate spots on top of head and a few very small ones on 

 sides, running into an unbroken double line of c. 52 on dorsal 

 aspect, very large, squarely stellate ; on the ventral side chroma- 

 tophores under head, continued in a line across yolk sac and on 

 dorsal aspect of intestine to vent, c. 28 on each side ; few others 

 spread over yolk sac ; double ventral series of c. 17, similar to 

 dorsal, behind vent. 



Fig. 14. — Coregonus clupeaformis about 1 week old, 13.5 millimeters 



13.5 mm., stage. Fig. 14. About 1 w^eek old. Total length 

 13.5 mm; length to vent 10.0 mm; greatest depth 1.6 mm; 

 diameter of eye 1.25 mm. Embryonic marginal fin unchanged in 

 shape, but slight suggestions of 5 dorsal finrays in anterior part, 

 pectorals very large. Still much yellow over yolk region which 

 is almost completely reduced, and w^hole head tinged with yellow- 



