St. Andrews Marine Laboratory . 47 



Most of the ova hatched about the sixth or seventh day — 

 tlie same period being mentioned by Mr. Holt — the larva 

 measuring about 2*2 millira. in length or a little more. The 

 increase in the red pigment was characteristic, the body under 

 a lens having a brick-red hue, with blackish chromatophores 

 scattered over the surface. I'he rounded reddish chromato- 

 phores of the embryo were now (in the larva) much branched 

 on the head, trunk, two caudal bars, and tlie rectal process, 

 and some had appeared around the oil-globule and at the 

 throat, as well as in the cardiac region. The two brownish 

 bars at the tail had a somewhat triangular or bluntly conical 

 form, and extended from the trunk to the border of the 

 marginal fin. A slight patch also occurred in the latter 

 dorsally, about midway between the caudal bar and the head. 

 The reddish pigment at the rectum passed downward to the 

 termination of the gut and abruptly ceased, a pale strand of 

 tissue being continued from it to the edge of the marginal 

 fin. The heart lay somewhat low in the subopercular region, 

 which was deeply pigmented. The finely ramified black 

 chromato])hores covered the entire region tinted reddish, so 

 that only the middle of the yolk-sac was translucent, and 

 even on this were a few much-branched red corpuscles. The 

 ventral surface of the yolk-sac, as well as other parts, had 

 numerous black chromatophores. By transmitted light the 

 reddish parts had a fine ruby-red hue. The eyes had a 

 similar colour, a few dark touches also being present. The 

 abundance of pigment obscured the otocysts and their two 

 otoliths. Even at this stage the larval fishes darted about 

 at intervals, after resting on the bottom or float with the 

 yolk-sac uppermost and the tail inferior. In Mr. Holt's 

 examples the oil-globule was ventral in position, but in ours 

 it occupied a more or less posterior position. 



After two days the pigment in the eyes had increased and 

 they were slightly iridescent. The black chromatophores 

 over the body were more abundant, while the bars behind the 

 vent were broader, especially the superior, which almost 

 touched the margin of the fin. The mouth was open and the 

 mandible was prominent. The oil-globule adhered to the 

 remnant of the yolk — nearly in the middle of the abdomen, 

 though slightly variable in position — in some having moved 

 upward and backward with the diminishing yolk. 



On the 1st of July the larval turbot evinced greater activity, 

 darting through the water at intervals and again resting on 

 the bottom. The increase in the black pigment rendered the 

 body dusky brown. The two posterior bars had spread out, 

 and finely ramified black pigment existed in both. The mid- 



