LAROCHE: DEVELOPMENT OF LARVAL SMOOTH FLOUNDER 



2.4 mm 



3.0 mm 



3.6 mm 



Figure 5. — Yolk-sac larvae of Pseudopleuronectes americanus. 



secondary rays are gradually added anteriorly. 

 The pelvic fin bud appears at =7 mm in postflexion 

 L. putnami larvae. Fin rays begin to develop by 7.6 

 mm, and development is completed by 13 mm 

 (Laszlo 1972). The pelvic fin bud appears at =6.6 

 mm in postflexion P. americanus larvae; and de- 

 velopment is complete by 7.3 mm. 



PIGMENTATION 



Liopsetta putnami 



The eyes of L. putnami are darkly pigmented at 

 hatching. Small external melanophores are scat- 

 tered over the head of the smallest larva (3.1 mm). 

 These melanophores appear to migrate ventrolat- 

 erally, appearing on the ventral surface of the head 

 between the isthmus and the cleithrum by =4.7 

 mm, and are aligned here on all specimens >5.4 

 mm long. This row often appears as a solid line of 

 pigment due to the expanded condition of indi- 



vidual melanophores. A melanophore appears at 

 the angle of the lower jaw between 4.8 and 5.4 mm, 

 and one or two melanophores are present at this 

 location on all specimens >5.4 mm. One or two 

 melanophores are present at the tip of the lower 

 jaw on most specimens >5.8 mm. A large stellate 

 melanophore appears below the lateral midline of 

 the head, anterior to the cleithrum at 5.2 mm. 

 Larvae >5.4 mm often have 4-6 melanophores, 

 internal and external, in this area. A few external 

 melanophores appear scattered over the head, on 

 and under the operculum, by 7.3 mm. Flexion and 

 postflexion larvae >6.6 mm rapidly acquire the 

 dense scattering of external melanophores charac- 

 teristic of juveniles. 



In the abdominal region small external 

 melanophores scattered over the dorsolateral sur- 

 faces of the hindgut are present on the smallest 

 larva (3.1 mm). An internal patch over the hindgut 

 is present on all specimens in the series. The small 

 external melanophores migrate ventrolaterally 



903 



