226 



Part TFL' — Thirteenth Annual Report 



or slightly oblique anteriorly, where trending to the oviduct. These 

 lamina 1 were covered with developing ova, which were considerably larger 

 than the ova found on the 7th September 1894. The largest ranged 

 from -2286 to -3810 mm., whereas these of September barely reached 

 •0762 mm. It is clear, therefore, that the environment of the turbot 

 had been favourable for the development of the eggs, and that, initial 

 dilticulties being overcome, it will yet be possible to retain the spawners 

 from season to season. This is the method, I think, to get over the egg- 

 bound condition, which is voluntary, and would disappear when the fish 

 felt itself to be in favourable surroundings and accustomed to confinement. 

 The anterior region of the ovary appeared to be somewhat thicker than the 

 posterior, and the ova slightly larger, but this may have been accidental. 

 The oviduct was occupied by a mass of the degenerating eggs. 



In an example 26 inches in length, the rugose laminse of the ovary 

 presented no degenerating eggs on their surface. The developing eggs 

 were somewhat smaller than in the previous example, viz., about -2286 mm. 

 In a third, 25 J inches long, a few degenerating eggs were found in the 

 interstices of the ovarian folds, though they were not seen on the surface ; 

 none of the eggs exceeded *1524 mm. In a fourth, measuring 25 J inches, 

 small masses of collapsed eggs lay on the surface of the ovarian folds. 

 The developing eggs in the wall of the ovary of this and the fifth and 

 sixth specimens had the same size as last, viz., '1524 mm. The fifth turbot 

 measured 23 inches, and the ovarian walls were somewhat thin, and the 

 rugose folds little developed. Small masses of degenerating eggs existed 

 here and there in pockets. In the sixth, which reached 21 \ inches, no 

 broken-down eggs occurred. In all, the remnants of the previous season's 

 eggs were being slowly got rid of, and apparently without serious 

 interference with the condition of the adults. 



Adults were again collected this year, and placed in the creek, but 

 though some unfertilised eggs were found in the water, no general 

 spawning has yet taken place voluntarily. Accordingly, it has been 

 necessary to remove the ripe eggs from the females, and the milt from 

 the males, and fertilise, a process which Mr Harold Dannevig has very 

 successfully carried out. The sketch of the development which follows 

 is taken from eggs thus manipulated, and already — that is, before the 

 beginning of July — 600,000 active larval turbot have been placed in the 

 sea. 



The ripe egg of the turbot (Plate VIII. Fig. 1) has an average 

 diameter of 1-0287 mm. ; the oil-globule measures 0*21 mm., and thus is 

 slightly less than the egg described in last Report,* which so nearly 

 approaches it in size. On extrusion, the healthy eggs are perfectly 

 buoyant — floating at the surface of still water, or suspended midway, as, 

 indeed, was observed in 1884. In some instances at Dunbar, however, 

 many of the eggs went to the bottom, probably because changes had 

 occurred by long retention in the ovary. The capsule is very distinctly 

 wrinkled — both in the fertilised and the unfertilised egg — quite as much 

 as in the lemon-dab. The oil-globule presents no special tint, and retains 

 a nearly uniform diameter in all the specimens, as Mr Holt has already 

 noticed. Like other forms, these eggs are sensitive in the early stages, 

 and with difficulty bear a journey, especially in warm weather, and it 

 would be well in such cases to delay until the blastopore has closed. 

 Those fertilised at 6 a.m. on the 22nd June were in the multicelled 

 condition at 6 p.m. (Plate VIII. Figs. 2 and 4), but the disc showed 

 certain peculiarities, the result of the journey in glass f vessels. Many of 

 the marginal spheres were much elevated, and the nuclei clearly defined 

 as slightly pinkish bodies by transmitted light (Plate VIII. Fig. 3). Many 

 * Part III. p. 222 et seq., 1894. . t Earthenware jars are better. 



