FISHERY BULLETIN: VOL. 87, NO. 3, 1989 



The caudal melanophore (Fig. 2D) becomes 

 located at the posterior hypural margin between 

 the superior and inferior elements, and remains 

 prominent during flexion. By the end of flexion it 

 is accompanied by 1-5 more melanophores which 

 outhne the posterior edge of the hypural plate. 



By the end of flexion the sides of the gut are 

 covered with melanophores, the dorsal midline 

 pigment is continuous to the head, and the 

 lateral midline series extends slightly forward of 

 the vent. A hne of pigment extends along the 

 isthmus; pigment outlines the jaw on its ventral 

 surface; and pigment increasingly covers the 

 snout, dorsal surface of the head, opercles, pec- 

 toral fin bases, and the walls of the gill cham- 

 bers. 



During postflexion and early juvenile stages 



the amount of head and body pigment continues 

 to increase. The lateral body stripe enlarges 

 dorsad, ventrad, and anteriad. Small mela- 

 nophores begin to outline the myosepta, initially 

 in the epaxial zone and later in the hypaxial zone. 

 Eventually the areas between the myosepta fill 

 with melanophores and the entire body and head 

 are covered (Fig. 3D). In addition to the devel- 

 opment of melanistic pigment, early juveniles 

 develop a layer of guanine which produces a 

 silvery sheen on the lower half of the body. This 

 silvery condition is retained throughout the 

 pelagic phase and is lost abruptly when the 

 pelagic young enter the tidepools at 25 mm 

 length (Feder et al. 1974). 



Fin pigment appears in early juveniles when 

 the dorsal spines become outlined with mela- 



Table 4. — Measurements (mm) of larvae and pelagic juveniles of Medialuna californiensis. Broken lines enclose 

 specimens undergoing notocfiord flexion and specimens below solid line are pelagic juveniles. 



754 



