92 Prof. M'Intosh's Notes from the 



chord was undifferentiated and Kupffer's vesicle still visible. 

 The black pigment was more distinct and some chromatophores 

 were slightly stellate. A few pigment-specks occurred on the 

 yolk at the sides of the alar expansions. The slits in the 

 otocysts were now ovoid and proportionally shorter than 

 yesterday. One or two otoliths, as a rule, were present. 



On the 25th February the otocysts formed broadly ovoid 

 chambers with two otoliths. The heart showed internal 

 papillse, but no trace of movement. The pectoral expansions 

 were larger and the notochord distinctly cellular. The pigment 

 spots were stellate, and some stretclied beyond the line of the 

 body into the yolk. The gut formed a pale band. The 

 following day (26th) distinct contractions occurred in the 

 trumpet-shaped heart, the lumen of the gut was distinct, the 

 alar expansions had increased, and Kupfifer's vesicle had 

 disappeared, except a trace in one example. The black 

 chromatophores were larger — eight or nine occurring on the 

 head. Very little pigment existed on the yolk — only a few 

 stellate patches close to the embryo. The tail almost encircled 

 the yolk. 



A considerable number were liatclied on the 27th February, 

 or twelve days after fertilization, the larva floating, as usual, 

 with the yolk-sac uppermost. They differed in the distribution 

 of the pigment from the larval cod, for the chromatophores 

 were scattered and did not form the characteristic bars of the 

 latter species, as indeed may be observed before extrusion. 

 On the following day (28th February) the lumen of the gut 

 was smaller than at first, probably from contraction, and the 

 liver formed a granular swelling on each side in ventral veins. 

 The pectoral folds were large. The yolk still showed a some- 

 what wavy structure, and many of the chromatophores had 

 become finely ramose, especially on the head. The larval 

 fishes became more active on the 1st March, darting forwards 

 on slight irritation, a feature familiar in salmon-rearing and 

 so often noticed during the development of marine fishes, and 

 which was emphasized so conspicuously in the Hatchery at 

 iJunbar, where the larval plaice, as soon as they had strength, 

 kept their snouts to the current. The otocyst now showed a 

 double margin, and a strand indicating the oesophagus 

 extended in front of the lens, and the liver was slightly larger. 

 Two minute vesicles occurred on the body opposite the pectoral 

 fins, and appeared to be the ends of the segmental ducts. The 

 notochord reached as far forward as the eye, and posteriorly 

 its point was nearer the caudal border. Embryonic fin-rays 

 extended a short distance outward from the notochord in the 

 tail. The rectal cone had moved slightly downward. 



