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Part III. — Thirteenth Annual Report 



the latter, — often broken up into a dorsal and a ventral band — and a small 

 fifth near the tip of the tail. In the more advanced and more active 

 larva?, with the yolk much diminished, the pigment is more continuous. 

 Those with a large amount of yolk swim with a wriggling movement. 

 By reflected light, the colour of these larval forms is greenish-yellow, and 

 thus it differs from the chrome-yellow of the younger stage. This change 

 of hue appears to be due to the development of the black pigment amongst 

 the yellow. The increase in the size of the pectorals in a few days became 

 marked, and though usually carried more or less obliquely they were fan- 

 shaped when viewed from above (PI. VII. fig. 3). 



The chief changes till the 20th April were the deepening of the marginal 

 fin both dorsally and ventrally, and the extension of the chromatophores 

 — both yellow and black — from the line of the body into the marginal 

 fin at the two conspicuous bars behind the vent, and the appearance of 

 stellate black pigment-corpuscles along the ventral edge of the fin. Stel- 

 late black corpuscles also occur on the abdomen, and the eyes are bright 

 silvery. The yellow pigment still forms a line over the medulla and the 

 first part of the cord. The caudal pigment-bar is chiefly of black cor- 

 puscles, only two or three yellow being present. The pectoral fins are larger 

 and have rays; the upward slant of the mandible and the reduction of the 

 yolk to a small round ball complete the features at this stage. 



2. On the Eggs and Larval Form of the Turbot, with Remarks on 

 the Gravid Forms at Dunbar. 



In several of the communications on this subject, an element of 

 uncertainty was present — since the eggs or larvse had been captured in the 

 free-swimming condition, and so little was known of the ripe eggs and the 

 larvae that the identification in most cases was open to question. It is 

 true the ripe eggs were removed from the female turbot by myself in 

 1884, and by Mr Holt in 1892, but in neither case could a ripe male be 

 obtained. Recently, Dr Canu, who is carrying out similar investigations 

 for the French Government at the marine station at Boulogne-Sur-Mer, was 

 able to fertilise the eggs and give a brief note of the development. The 

 perseverance of Dr Fulton, and the practical skill of Mr Dannevig at the 

 Dunbar Hatchery of the Board have at length made it possible to give a 

 definite account of the development of this species in Britain. 



After the operations connected with the spawning of the plaice were 

 concluded last year, the turbot was one of the species next taken in 

 hand, for its period of reproduction is considerably later, and therefore 

 fitted in very well with the earlier plaice. Though fine examples of both 

 sexes were obtained, spawning did not occur. The turbot were first kept 

 in the closed creek, and then removed to the spawning pond, which, when 

 soles arrived, was divided by a canvas partition into two compartments. 

 Subsequently they had the entire space. The reason why the ripe turbot 

 did not spawn, under conditions of food and environment that were 

 deemed to be most favourable, and which had succeeded in the case of the 

 plaice, merit careful consideration. Injury during capture in some cases 

 may have weakened the gravid fishes, but not in all, and the plaice did 

 not seem to be seriously affected by this cause. They suffered at first : not 

 after they were accustomed to confinement. In examining the turbot in 

 the spawning pond in September, a considerable number had patches of 

 superficial ulceration on the white (right) side, chiefly on the opercular 

 region and the tail. A single patch occurred on the former — varying in 

 size from J to \\ inches in length and f inches broad at its widest part, 

 and one on each side of the tail of smaller size. These were the points 



