506 



BULLETIN OF THE BUREAU OF FISHERIES 



end of the gut is also heavily pigmented. In water of about 39° the larva grows to 

 5 mm. in length, and the yolk is absorbed (fig. 258) in 12 to 14 days. In 5 to 7 

 weeks after hatching, at a length of about 6 mm., the vertical fin rays begin to appear 

 and the left eye has moved upward until about half of it is visible above the dorsal 

 outline of the head, while in larvae of 8 mm. the whole left eye shows from the right 

 side and the fins are fully formed. Metamorphosis goes forward so rapidly there- 



Fio. 257— Egg 



Flo. 258.— Larva, 19 days old, 4.5 millimeters 



Fig. 259. — Larva, 5 millimeter 







)■ i^ 



^-S^- ! 







Fig. 260.— Larva, 8 millimeters 

 WINTER FLOUNDER (PseudopUuronectes amerkanus) 



after that within three days, according to WiUiams,^^ the left eye moves from this 

 position to the right side of the head, the pigment fades from the blind side, the 

 eyed side becomes uniformly pigmented, the little fish now lies and swims with the 

 blind side down, and when only 8 to 9 mm. long its metamorphosis is complete. 



" Bulletin, Museum of Comparative Zoology at Harvard College, Vol. XL, 1902-3, No. 1, pp. 1-58, pis. 1-5. See also Sullivan 

 (Transactions, American Fisheries Society, Vol. XLIV ,1914-15, pp. 125-136, flgs. 1^) and Breder (Bulletin, U. S. Bureau of 

 Fisheries, Vol. XXXVIII, 1921-22 (1923), p. 311) 



