43 



There is therefore no question as to the smallest of the young fish 

 not being able to obtain the amount of food required. The fish 

 were measured periodically, and the dates and results of the 

 measurements made wdll be found in Table V. 



There are three points which are apparent from the measure- 

 ments of the young plaice. The first is that growth was not 

 stopped during the winter : secondly, the rate of growth, for the 

 time they have been under observation, has not been regular ; 

 and thirdly, during the month of January growth was more rapid 

 than in either December or February. 



The average sizes of the young plaice at each time of measure- 

 ment and also the average growth increments are here given. 



Date 24th Aug. -Ith Oct. 1st Xov. 2nd Dec. 5th Jan. Ist Feb. 7th Mar. 7th Apr. 19th May. 19th June. 

 Average size 4-0 4-7 5-7 6-3 6-6 7-3 7-7 8-2 8-8 9' 6 cm. 



Average Increment 0-7 1-0 0-6 0-3 0-7 0-4 0-5 0-6 0*3 cm. 



During December the J^oung plaice made attempts to leave 

 the tank, and seven of them escaped by means of the overflow 

 into the next tank. They were returned. 



There are only three turbo o now living out of the five put 

 into the tank, but these differ from the 3'oung plaice in that during 

 December, January and February no increase in length was made. 



HALIBUT, Hiiypoglossus vulgaris. 



Owing to the kindness of several people at North Shields 

 >fish quay, and chiefly to that of Mrs. J. A. Taylor and Mr. T. Dunn, 

 it has been possible to obtain measurements and otoliths from 

 forty-eight hahbut. 



The age of the halibut is shown on the otoliths, which are 

 built up of areas or zones alternately opaque and more or less 

 transparent when viewed by transmitted light, and alternately 

 white and dark when viewed by reflected light. Fig. 1, Plate II., 

 is a photograph by reflected light of the otoHth of a hahbut, 61 

 cm. long, landed at North Shields, 10th iVpril, 1916. Very faint 



