220 



Part III. — Thirteenth Annual Report 



IV.— CONTRIBUTIONS TO THE LIFE-HISTORIES AND DE- 

 VELOPMENT OF THE FOOD AND OTHER FISHES. By 

 Professor M'Intosh, M.D., LL.D., F.R.S., F.R.S.E., &c, St 

 Andrews Marine Laboratory. (Plates VI., VII., and VIII.) 



CONTENTS. 



PAGE 



1. On the Eggs and Larva? of the Long Rough Dab, .... 220 



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



Forms at Dunbar, ....... 224 



3. On a Larval Pleuronectid (Dab ?) with a Deep Body, . . .229 



4. On the Spawning Period of the Armed Bullhead and the Vitality of its * 



Eggs, . 230 



5. On the Post-Larval Stage of Crystallogobius Nilssonii, . . . 232 



6. On a Post-Larval Form resembling a Goby, . . . .232 



7. On a Peculiarly Coloured Plaice, ...... 234 



1. On the Eggs and Larv,e of the Long-Rough Dab 



(Drepanopsetta plate ssoides). 



During the trawling expeditions of 1884, an egg was frequently found 

 in spring, especially during March and April, which was distinguished 

 from all others by the large size of the perivitelline space, — that is, the 

 space within the transparent capsule or zona in the early stages of the 

 egg. It was mentioned in the report on trawling that these ova were 

 one-third larger than the majority of the pelagic eggs, and resembled 

 hydropic ova. The latter condition, however, was only apparent, and 

 they were in all respects healthy, the advanced embryo with its yolk-sac 

 lying in the centre of the transparent capsule. These eggs were widely 

 distributed all along the eastern coast from the south of St Abbs Head 

 to the Moray Firth, so that they evidently belonged to a common species. 

 Though ripe long-rough dabs were seen in the dead condition in March 

 1884, and the eggs observed to be pelagic, yet, as this occurred during a 

 violent storm, no opportunity was available of doing more than noting 

 their condition, which, on issuing from the ovary, differs, as will by and 

 by be shown, from their subsequent state, and thus the connection between 

 them and the foregoing was not made out. Every season (viz., in March, 

 April and May) since that date these eggs have been brought in greater 

 or less numbers to the Marine Laboratory and hatched. A figure of 

 the same egg was also shown me by Mr J. T. Cunningham in 1885, 

 but he likewise had not ascertained the form to which it belonged, for 

 in 1887 * he observes that he had not been able to hatch it, and that 

 no similar egg had been obtained from an adult fish. Further remarks 

 on the egg and newly-hatched larva were made in the ' Pelagic Fauna 

 of St Andrews Bay ; ' f the advanced embryo tending to the upper 

 arch of the egg in floating, and presenting, along the sides, minute 

 yellowish (chrome) and black chromatophores, which in most cases were 

 still unbranched after hatching. In the 1 Researches ' J the same egg 

 was again alluded to, and the early post-larval fish figured. It * presents 

 ' three distinct yellowish bars behind the vent, another at the latter, 



* Trans. Roy. Soc. Edin., vol. xxxiii., p. 105, PI. vii., fig. 2. 



t Seventh Annual Report of the Fishery Board for Scotland, p. 270, PI. iii. figs. 1-3, 

 1889. 



X Trans. Roy. Soc. Edin., vol. xxxv. part iii., p. 853, PI. xviii. fig. 2, Feb. 1890. 



