FISHERY BULLETIN; VOL. 78, NO. 4 



eter from 1.1 to 1.4 mm, averaging 1.2 mm. Yolk 

 diameter ranged from 0.9 to 1.2 mm, averaging 1.1 

 mm. No oil globules were obvious in newly fer- 

 tilized eggs. At 5° C hatching began on the 25th 

 day after fertilization. Newly hatched larvae were 

 3.1-3.6 mm long. 



DISTINGUISHING FEATURES 



Characters useful to distinguish larval L. put- 

 nami andP americanus from other Gulf of Maine 

 flatfishes are: number of myomeres, 34-38 and 

 38-40; hatching length, 3.1-3.6 mm and =2.4 mm; 

 number of dorsal fin rays, 48-60 and 60-76; 

 number of anal fin rays, 34-41 and 44-58; and 

 presence of a single vertical band of melanistic 

 pigment across the postanal region of both species. 



Characters useful to distinguish yolk-sac larvae 

 of L. putnami from P. americanus are: percentage 

 snout to anus length/standard length, averaging 

 43.6% vs. 33.3%; presence of eye pigment at hatch- 

 ing vs. absence of eye pigment at hatching; length 



at hatching, 3.1-3.6 mm vs. =2.4 mm; and length 

 at yolk-sac resorption, —5.2 mm vs. —3.7 mm. 



Characters useful to distinguish larval L. put- 

 nami from P. americanus are: absence of internal 

 melanophores over the notochord vs. presence of 

 internal melanophores over the notochord; length 

 at which gut loops, =5.5 mm vs. =4.3 mm; and 

 absence vs. presence of anal fin pigmentation in 

 specimens <6.3 mm. 



GENERAL DEVELOPMENT 



(Figures 1-8) 



Reared L. putnami were 3.1-3.6 mm long at 

 hatching. The smallest field-collected L. putnami 

 larvae were =3.5 mm long. Newly hatched field- 

 collected f?amer/canus larvae were =2.4 mm long. 

 Theyolksacisresorbedby =5.2 and =3.7 mm in L. 

 putnami and P. americanus . The gut loops by =5.5 

 mm in L. putnami and between 4.2 and 4.4 mm in 

 P. americanus. The notochord begins to flex in L. 

 putnami and P. americanus at =6.0 and =5.0 mm; 



5.2 mm 



5.4 mm 



5.9 mm 



Figure 2. — Preflexion larvae of Liopsetta putnami. 



900 



