SILVER MT7X.LET 



405 



PIGMENTATION 



Pigmentation of the embryo and of the larvae 

 through the yolk-sac stage has been described and 

 illustrated. At about 3.7 mm. total length, the 

 pigmentation continues to consist essentially of 

 pigment spots along the dorsal and ventral aspects, 

 with scattered melanophores on the head, sides 

 of body, and throat (fig. 8). Development of 



pigmentation from this stage is a process of inten- 

 sification and spreading onto the head and sides 

 of the body, so that by a larval size of about 

 14.5 mm. the specimens are so densely covered by 

 large and small pigment spots as to appear almost 

 black (this is especially intense on the caudal 

 peduncle). No pigment is present on any of the 

 fins during this period. The development of 



2 4 6 8 10 20 40 60 80 100 200 400 600 



STANDARD LENGTH IN MM. 

 Figure 17. — Relation of head length to standard length.' 



' Specimens below 25 mm. long are plankton and dip-net material from open ocean; ttiose 27 to 122 mm. are seine material from marsh and beach are-is 

 and those 151 mm. and larger are the specimens from the spawning school. 



