NOTES AND MEMORANDA. 401 



hatching it has deepened to a very red orange by reflected, bright 

 red rust-colour by transmitted light. A day or two after hatching 

 it is an intense fiery orange by reflected, inclining somewhat to 

 crimson by transmitted light. This coloration is more closely 

 approached by the hybrid turbot and brill larvae, described by 

 Professor Mcintosh (Reps. S. F. B., 1891), than by any other 

 British form with which I am acquainted. It appears from subse- 

 quent observations by the same author (Ann. and Mag. Nat. Hist., 

 July, 1892) that the true-bred brill larva does not materially differ 

 from the hybrid. 



It had been surmised by Professor Mcintosh and myself, in the 

 absence of any exact information on these stages of the turbot, that a 

 minute Pleuronectid ovum and larva, the species F of Mcintosh and 

 Prince (op. cit.), might prove to belong to that form. The present 

 observations show that this is not the case, since, apart from the 

 differences in dimensions of the ovum, the pigmentation is entirely 

 different, and the turbot at no stage exhibits the peculiar reticulate 

 structure of the epidermis which always characterises species F. 

 Hence the affinities of the latter must be sought elsewhere, probably 

 amongst the top-knots. 



A remarkable tendency was observed, which may render the 

 artificial culture of the turbot a matter of difficulty. 



In the several clutches which I fertilized the ova sank to the 

 bottom at from two to seven days after fertilization. They did not 

 appear unhealthy, and continued to develop as well as such as re- 

 mained floating, but it was impossible to separate them from the 

 dead ova, which always form an unpleasantly large item in the con- 

 tents of a hatching jar. 



The same behaviour was exhibited by four different clutches of ova 

 fertilized for me by fishermen at sea : in one case I am informed that 

 the ova sunk after only a few hours, though at the end of two days 

 they still looked healthy ; they were then thrown away, on the ground 

 that if they were not dead they ought to be. 



Thus we have pretty strong evidence that there is a general 

 tendency in the turbot's egg to sink sooner or later after fertiliza- 

 tion, and we know from Raffaele that this is a regular feature in 

 the development in ovo of Trachinus ; it happens also occasionally 

 in the gurnard and some other forms. 



I imagine that the successful culture of a pelagic ovum which 

 assumes a demersal nature at an uncertain period will be difficult. 



Later Stages. — Like the ova and larvae, the younger metamor- 

 phosing stages seem to have escaped the notice of naturalists. In 

 fact, the earliest examples which could indubitably be referred to 

 this species are those enumerated by Mr. Cunningham in an earlier 



