of the Fishery Board for Scotland. 345 



Thus the spawning period is normally related to the period most 

 advantageous for the settlement of the young metamorphosed plaice on 

 the beaches, both varying together according to the temperature. In 

 this respect the reproduction of the plaice is comparable to other cases, 

 as, for example, the nesting of birds. The seasonal temperatures also, 

 it may be said, are related to the selection of the spawning ground, the 

 position of which is not, as some imagine, a matter of indiflerence; so 

 that the plaice, although its progeny settle on the margin of the sea, 

 spawns in spring (in cold water) some distance from the shore, while 

 the flounder, whose young have a similar habitat, may spawn quite close 

 to the shore in summer (when the water is warm), and its eggs hatch 

 in a few days. In both cases the loss of eggs by stranding on the beach 

 is reduced to a minimum, while the advantageous habitat is obtained. 



The average growth of the plaice in the Solway Firth, then, in its 

 first summer — from the time development begins about the middle of 

 March to the arrest of growth about the end of October — may be said 

 to be, on the average, about 60 millimetres, or 2^ inches. The large.st 

 individuals may measure 25 mm. more, or a little over 3 j inches, while 

 specimens as small as 33 mm., or ly^ of inch, may be procured as late 

 as November. The series is then not absolutely, but almost quite, 

 separated from the series of the preceding year. 



In the spring of the next year, as we have seen, the young plaice 

 are about the same length, and the average size of one of these 

 plaice one year old, computing from the beginning of embryonic 

 life, or the beginning of larval life, is about what is above stated. With 

 the rising temperature of April growth recommences, so that at the 

 end of the month the average length is 6 or 7 mm. greater. In May 

 growth is no doubt accelei-ated, and in June especially growth is I'apid, 

 so that at the end of that month the average size is about 90 mm., or 

 3| inches, showing an increase of 30 mm. 



These plaice are in their second year, but the collections made 

 of this second series are not complete, and I think I may say, from an 

 examination of their Tables, that the same remark applies to the collec- 

 tions made by others. The particulars are given in the following Table : — 



[Table. 



