324 THE FLOUNDER FAMILY. 



Besides, there are in some the pale precursors of the pigment- 

 specks, which appear blackish by transmitted light. The 

 notochord was visible throughout, the lenses in some were 

 faintly indicated, and the otocysts appeared as elongated 

 thickenings with a longitudinal slit, as in the green cod 1 . 

 The heart was also distinct. The zona was thin, and readily 

 ruptured even when the egg was carefully lifted. 



The following day the blackish pigment formed dark bands, 

 especially when viewed on a white surface, and the next day a 

 faint yellowish tint was visible under a lens. The tail formed 

 a blunt knob projecting beyond the yolk. 



The yellowish hue was more distinct on the 30th March. 

 On the head it was somewhat diffused, as the chromatophores 

 had given off branches. The rows of rounded specks along the 

 sides are only faintly tinted. Both yellow and black pigments 

 were present. The latter (black) were very finely ramose on 

 the dorsum of the snout and on the head, as well as behind the 

 otocysts. Distinct muscular twitchings of the body occurred 

 on this day. 



On the 1st April, the embryo more than stretched across 

 the egg (PI. Ill, fig. 21); but in most the pigment-corpuscles 

 remained simple. The heart was minutely papillose internally 

 and trumpet-shaped. Slow contractions occurred at intervals. 

 Most of the yolk was absorbed, and the alimentary canal formed 

 a pale band in front. The otocysts sometimes differed in size. 

 The day after, most of the yellow chromatophores in some were 

 ramified, so that the colour was diffuse, but in others the 

 pigment-specks remained circular. A few small black points 

 were mingled amongst the yellow along the sides of the body. 

 At this stage the yolk was quite free from pigment. 



A few were hatched on 3rd April, and many next day. It 

 is possible that the conditions as regards still water and low 

 temperature may have considerably delayed hatching. A speci- 

 men removed from the capsule on the latter date (4th April, 

 PI. XII, fig. 11) differs in some respects from that figured by 

 Holt, viz., a larva about half a day old, since the pigment is 

 not definitely marked in his sketch. Moreover, the former 

 1 Twelfth Annual Report S. F. B. Pt. Ill, p. 219, PI. II, fig. 8. 



