LAROCHE: DEVELOPMENT OF LARVAL SMOOTH FLOUNDER 



flexion is completed by —7.1 and =6.6 mm; and the 

 free tip of the notochord disappears by 7.6 and 7.3 

 mm. Transition from pelagic to benthic habit oc- 

 curs at =7.3 mm in L.putnami. The largest pelagic 

 field-collected L. putnami larva was 7.3 mm, and 

 the largest specimen, 7.6 mm, had assumed the 

 benthic habit in the laboratory. Transition from 

 pelagic to benthic habit usually occurs between 

 6.0 and 7.0 mm in P. americanus. The smallest 

 benthic-collected P. americanus was 5.7 mm, and 

 the largest pelagic-collected larva was 7.4 mm 

 long. Formation of pectoral and pelvic fin rays is 

 completed between 8.5 and 13.0 mm (Laszlo 1972) 

 in L. putnami and by =13 mm in P. americanus, 



marking the end of the transformation and begin- 

 ning of the juvenile period. 



MORPHOLOGY 



(Tkbles 1-3) 



Various body parts were measured on 40 L. put- 

 nami (3.1-7.6 mm) and 64 P. americanus (2.4-7.3 

 mm* larvae to examine developmental morphol- 

 ogy. Body proportions are summarized and com- 

 pared in Table 3. 



The most important morphological character 

 for separating L. putnami from P. americanus, 

 particularly during the yolk-sac and preflexion 



6.3 mm 



6.4 mm 



6.6 mm 



Figure 3.— Flexion larvae of Liopsetta putnami. 



901 



