542 Transactions. 



again when the stocks of flounders kept in the ponds are strictly- 

 separated. In connection with the occurrence of the oil -glo- 

 bules in these eggs, attention may be drawn to a hypothesis 

 advanced by Dr. J. T. Cunningham in the " Journal of the 

 British Marine Biological Association" (vol. i, p. 48), in which 

 he seeks to trace a connection between the occurrence of oil- 

 globules in the yolk of the egg and the presence of much or 

 little oi)y matter in the tissues of the parent fishes. This point 

 also can be looked into when the species have been worked 

 out separately. 



In about four days after the ova were obtained and fer- 

 tilised the larvse began to hatch out, and they were kept in 

 the boxes for about fourteen days and then liberated. Speci- 

 mens of these larva? were preserved and mounted every day, 

 and drawings were made by Mr. Anderton, but until the identity 

 of the species is established it is thought undesirable to re- 

 produce these, or to publish any notes on them. 



We have reason to believe that the fish in the ponds either 

 cannot get rid of their ova without difficulty, or do not do so 

 for some unexplained reason, in the shallow water. Some 

 two hundred fish in all were kept in the pond, of which over 

 one-fourth were mature females, yet only a very few appear 

 to have liberated their eggs. The mature fish taken in June 

 of this year were obtained only in deep water, while last year 

 no females were got at all in the trawl-nets on the trip of the 

 24th July. It seems as if the fish moved out into deep water 

 at spawning- time, but whether this is connected with the more 

 effective distribution of the species, or whether the greater 

 pressure of the water in any way facilitates the extrusion of the 

 ova, is problematical. It may be only a question of temperature ; 

 while the pond water frequently cooled down sometimes as low 

 as 5° C, that of the ocean at the same time probablv never 

 fell below 10°. 



Another piece of knowledge gained is the hardiness of both 

 species of Rhombosolea. They seemed to be unaffected by the 

 low temperatures which prevailed in the ponds during the winter 

 months, except perhaps in the retardation of their sexual ma- 

 turity. 



During October it was noticed that several of the fish in the 

 ponds were showing sores. These were found on both the upper 

 and under sides, but appeared most commonly on or near the 

 base of the pectoral fins, and seemed to pass into ulcers which 

 ate down to the bone, in some cases proving fatal to the fish. 

 They were not confined to the fish in the pond, though rather 

 frequent among them, but were found in the fish taken in the 

 bay with seine nets. The cause is obscure, but the mature 



