372 NORTH SEA INVESTIGATIONS. 



fifths of the distance from the first hgemal spine to the caudal peduncle, 

 whilst spent ovaries have always been longer. It is as yet too 

 early to summarise the proportional differences in the lemon sole, as 

 the spawning period is apparently very protracted in individuals as 

 well as in the species ; but it seems that a spent ovary is always 

 wider and longer than an immature one. Nor is it yet possible to 

 ascertain to what extent the shrinkage of a spent ovary is carried, 

 either in the sole or in the lemon sole, or whether, by the absorption 

 of the small active ova, an entirely inactive germinal epithelium 

 is ever met with in spent examples. Should this occur, and no 

 retained ova be present, it would be extremely hard to distinguish 

 the condition in a lemon sole. An instance, which I suppose to be 

 exceptional, of the degeneration of a spent ovary has come under my 

 notice in the sole. The wall of the posterior portion of either ovary 

 had become disintegrated, and fragments of the germinal epithelium 

 had consequently found their way into the general cavity which 

 lodges the ovary, whilst on the blind side similar matter, containing 

 both active and inactive ova, had penetrated between the muscles of 

 the interhsemal ridge and between the bases of several of the anal 

 fin-rays and the skin. I suppose that this process of atrophy would 

 in time have extended to the rest of the ovary, but clearly it would 

 not result in any condition resembling that of an immature example. 



It need hardly be said that when an ovary agrees with the im- 

 mature condition in other respects, but exhibits an activity in the 

 germinal epithelium, it is reasonable to suppose that the fish is 

 about to spawn for the first time. Thus the distinction between an 

 ovary ripening for the first time and for any subsequent time is 

 not hard, so long as it is only in the early stage of maturation. The 

 difficulty is felt when the organ has attained a considerable deve- 

 lopment, such as would, in the case of a fish that had already 

 spawned, suffice to obliterate the traces by which such condition 

 might othei'wise have been recognised. 



It has been difficult, notably in the case of the turbot and brill, to 

 obtain svifficient numbers of females at the critical sizes, since 

 amongst the smallest members of any species brought to market 

 the males are always infinitely more numerous than the females ; 

 the converse, of course, holding good amongst the larger examples, 

 which are of less interest for the purpose in hand. The accom- 

 panying figures must not be taken as indicating the relative abun- 

 dance of the sexes at the different sizes, since, in selecting fish 

 for examination, I have often had to reject large numbers of males, 

 from want of time for the record of their condition. 



I may here remark that, according to my experience, whenever 

 a catch of fish from an offshore ground, especially in the spawning 



