﻿24 



I have already now and then touched on circumstances which are 

 connected with the propagation of the plaice; it has been mentioned, for in- 

 stance, that there is a noticeable difference' between the average size of mule 

 and female fish, the former .being a little smaller; nor do they ever reach 

 the maximum length of the females. This, however, was not sufficient 

 completely to efface the differences between the annual series in the ta- 

 bles, even if both sexes were measured together, but it may to some degree 

 have prevented the groups from standing out so clearly as they would have 

 done if the sexes had been separated. — 



Also the breeding-time of the plaice has been mentioned already, and it 

 has been shown by means of the occurrence of the easily recognizable pe- 

 lagic eggs in Famo sound (in the years 1891 — 94) that the breeding-time 



of all the sizes of the plaice at Esbjerg. — Loc. cit. no plaice is mentioned in 

 .ran. — June smaller than 1',.. inch in length, but in January, April, ami May some 

 are l 1 /, inch long, and are explained by Owmmgham as tin* fry of the year from 

 this winter; they are always found, however, as the smallest specimens of a large 

 group reaching 2 — 3 — 4 — 5 etc. inches in length; he says also, loe. cit. p. 349: >I do 

 not understand why comparatively few of these young plaice were taken in May. 

 My supposition, that they are the fry from the preceding winter, will explain this. 

 Cmp. table III for instance, but also my remarks p. 16). 



Cunningham says further, loc. cit. p. 34!); -At the beginning of June another 

 outburst appears- ; these individuals may probably be explained as the fry of the 

 year (the (• group"; yet they are not quite newborn, but C 1'., inches long. Holt, 

 who has gathered the materials, has evidently not got the very smallest specimens. — 



Xow 1 do not intend with these remarks to maintain that I, in all cases, can 

 decide the age and growth of the plaice; but my method gives a better survey of 

 the whole matter than those which have formerly been employed, and my results 

 can easily be controlled, revised, and supplemented, which is an decided advantage 

 in a scientific method. 



Dr. Wemyss-Fulton has in -Report Scot. Fishery Board" given the first contribu- 

 tions to a more rational investigation into the biology of the plaice and other fish, 

 and particularly pointed out the different dwelling-places of the different sizes in 

 a very careful manner. His results from the Scotch seas are nearly analogous to 

 mine from our own, but the commingling of large and small races of plaice which 

 we have, seems to have no analogue in the Scotch seas; on the other hand we 

 may find smaller races at the south of England than on the eastern coats of Scot- 

 land. — He has to a great extent labelled the fish with labels like, or resembling, 

 those which I formerly used. In this way he has also given contributions to the 

 question of the growth of the fish; the latter, however, on the whole, do not 

 seem to have grown so much by far, as those with the new labels which I have 

 used in the Limfjord. — 



In later years has E. 11'. J,. Holt made investigations into questions'^ which are 

 nearly related to this, both in the German Sea and west of Ireland; also Prof. 

 M'Intosh, C. Williamson a. o. have worked at this question. For further particu- 

 lars see > Contemporary Work'! in » Report of the Fishery Board for Scotland" 

 which every year renders an account of work of this nature ami of fishery -litem 

 ture on the whole. 



