NOTES ON TELEOSTEAN OVA AND LARVAE. 21 



Solea vulgaris, nor distributed fairly regularly about the yolk as in 

 ;S^. variegata and S. Intra, but were arranged so that the majority of 

 them formed a circle round the yolk outside the margin of the blasto- 

 derm, while there were also a number closely aggregated into a group 

 at the vegetative poles. 



Four days later (on tlie 19th) the larva was found to have hatched 

 out (see Fig. 11) and was then probably in its first day of larval life. 

 Its total length was 3"46 mm. and its pre-anal length 14 mm. The 

 yolk-sac at this stage is very globular, the oil-globules being mostly in 

 the ventral part of it. The head, body, unpaired fins and pectorals 

 (which later become rather conspicuous), and yolk-sac are liberally 

 sprinkled with dull, pale yellow chromatophores, from the well-marked 

 rounded centres of which ramify dendritic outgrowths. There are 

 black pigment spots having generally the same distribution but less 

 numerous, especially on the yolk-sac and unpaired fins. The caudal 

 region, where embryonic fin-rays are making their appearance, is 

 unpigmented. Black is beginning to appear in the eyes. Two days 

 later the yolk is reduced to about the size of the head, but still shows 

 several oil-globules also reduced. The total length is about 3-7 mm. ; 

 from the snout to the anus about 1*52 mm. The eyes are black 

 with greenish tints. The midbrain is well developed and the 

 frontal region prominent — of the typical Solca type. The mandi- 

 bular region is also well developed, but the mouth is not yet 

 open. The gut now has a ventral bend above the posterior half of the 

 yolk-sac. The pigment is practically unchanged, except for a con- 

 centration into marginal patches along the unpaired fins — six in the 

 anal and nine in the dorsal fin — each patch consisting of a mass of 

 dendritic chrome-yellow, usually with a somewhat dense black spot in 

 the centre. The pectoral fins are large, well pigmented, and generally 

 in active movement. The following day saw a further reduction- of 

 yolk, but there was still some left. The gut has now a pronounced 

 U-shaped bend. The mouth is apparently about to open. The 

 pigmentation of the unpaired fins shows further concentration into 

 patches along the extreme margin. Yellow (dull brown by trans- 

 mitted light) forms the greater part of each patch. The rest of 

 the fins and body are also well covered with dendritic and irregular- 

 shaped chromatophores. The frontal region is further developed 

 and certainly constitutes a remarkable feature of the larva, but 

 is nothing like Holt's drawing of his "Species I — Solca {i)" (11a, Figs. 

 34 and 35). 



On the 23rd (viz. four days after the larva was first observed) it 

 showed signs of ill-health and the tip of the tail had become shrunken 



