FISHERY BULLETIN: VOL. 78. NO. 4 



6.9 mm 



^^^^^■■■: 













9.8 mm 



Figure 8. — Flexion, transforming, larva (6.9 mm) and postflexion, transforming, larva (9.8 ram) oiPseudopleuronectes americanus. 



melanophores are present at the articulation of 

 the lower jaw on larvae >3.4 mm. A few external 

 melanophores appear on the snout and operculum 

 of preflexion larvae >6.6 mm. Postflexion larvae 

 ( >5.8 mm) rapidly acquire a covering of external 

 melanophores, characteristic of juveniles, as 

 transformation proceeds. 



External melanophores are scattered over the 

 abdominal region of the smallest larva (2.4 mm) 

 with greatest concentrations along the dorsal sur- 

 face of the body and on the ventrolateral surface of 

 the yolk sac. Internal melanophores are present in 

 a patch over the posterior hindgut near the anus 

 and over the middle of the gut. By 3.6 mm pigmen- 



906 



tation disappears from the dorsolateral surface of 

 the abdominal region, and the melanophores 

 which had been scattered over the yolk sac are on 

 the ventrolateral surfaces of the body. Some of 

 these form a row which is often expanded and 

 appears as a solid line between the anus and the 

 cleithrum with some on the ventrolateral surface 

 on each side of the line. Also, by 3.6 mm, one to 

 several internal melanophores appear in the vicin- 

 ity of the pectoral fin base posterior to the clei- 

 thrum. By 4.4 mm, internal melanophores are 

 present over the notochord in this region. No 

 further pigmentation changes occur until exter- 

 nal melanophores begin to appear scattered over 



