FISHERY BULLETIN: VOL, 78, NO. 4 



4.0 mm 



4.4 mm 



5.3 mm 



Figure 6. — Preflexion larvae (4.0 and 4.4 mm) and flexion larva (5.3 mm) of Pseudopleuronectes americanus. 



becoming scattered on only the ventral surface of 

 the body and yolk sac by 4.8 mm and form a row 

 along the ventral midline on all specimens larger 

 than ==5.2 mm. This row extends from the clei- 

 thrum, where it is continuous with the row on the 

 ventral midline of the head, to the center of the 

 abdominal region where it becomes indistinct, 

 merging with a group of melanophores scattered 

 on the ventrolateral body surface between 6.6 and 

 7.0 mm. Specimens >7.0 mm rapidly acquire the 

 dense scattering of external melanophores over 

 the body surface characteristic of juveniles. 



Small external melanophores are scattered over 

 the postanal region, and a vertical band of concen- 

 trated melanophores of various sizes is present 

 across the center of the postanal region in the 

 smallest larva (3.1 mm). The scattered external 

 melanophores migrate ventrolaterally and are 

 present only on the ventrolateral surfaces by —4.6 

 mm. An irregular row of melanophores extends 



from the anus to the vertical pigment band along 

 both sides of the ventral midline, and a single 

 irregular row of melanophores along the ventral 

 midline extends posteriorly from the pigment 

 band on specimens 4.3-5.4 mm long. Usually 

 one to several small melanophores appear some- 

 what separated from the row and located just 

 anterior to the notochord tip. The vertical pigment 

 band is distinct on larvae <5.4 mm, but it is 

 usually represented by only a few large stellate 

 melanophores on larger larvae. These melano- 

 phores become indistinguishable from other ex- 

 ternal melanophores which become scattered over 

 the body on large larvae, >6.6 mm, indicating the 

 initial development of the juvenile pigment pat- 

 tern. 



The fin folds of the smallest L. putnami larva 

 are not pigmented. At =5.2 mm one or two 

 melanophores move from the body onto the fin 

 membrane just anteroventral to the notochord tip. 



904 



