of the fishery Board for Scotland. 



135 



Plaice received from Aberdeen, April 1, 1905, and collected 

 JUST BEFORE that date. 



MALE. 



(1) IS'lcm.y immature. — Otolith shows two zones, the third of the 

 current year may have begun, but shows no distinct contrast with the 

 second zone. The scales also show two zones, but not so easily dis- 

 tinguished. 



FEMALES. 



(1) 12cm. long, immature. — Only one zone, or central area ; fish, 

 therefore, one year old (fig. 9, pi. vii.). 



(2) 14cm., immature. — Otolith shows only one undivided area, may be 

 considered one' year old. Scales also show no division into zones. 



(3) 15cm., immature. — Two distinct zones in otolith, outer zone 

 sharply defined from central region, indicating two years' growth. 



(4) 15cm., immature. — Two distinct zones in otolith ; the central 

 region is much smaller than the whole otolith of (2), and does not show 

 distinct lamination as that does. The calcified cartilage of the coracoid 

 also shows two zones, but the boundary line is rather faint. 



(5) 16'7cm., immature. — Otolith with central region and one outer zone 

 separated by distinct boundary line. On the outer border there are a few 

 opaque layers, which may be the commencement of this year's deposit, 

 but they are not delined by a distinct boundary from the second zone. 



(6) 20'7cm., immature. — Otolith shows four distinct zones. It seems 

 difficult to believe that this fish, not quite 8J inches long, and quite 

 immature, should be really four years old, in which case it would be 

 at least five years of age before it spawned for the first time. 



(7) Plaice, 22'dcm., immature. — Only one distinct boundary, with very 

 dark and opaque layers outside it. Several fainter lines in the central 

 area, but these I regard as all occurring in the first year's growth. 



With the exception of (1), (2), and (6), therefore, all these specimens 

 were two years old and at the commencement of their third year. 



Larger Plaice, caught 21 miles S.S.E. of Aberdeen, about 

 March 8, 1905. 



MALE. 



(1) 26-/ cm., immature. — Testes a mere narrow band along the anterior 

 iuterspinous bone at posterior border of body cavity. Otolith shows 

 three complete zones, with no distinct indication of the beginning of the 

 fourth. May be taken to be three years old. 



FEMALES. 



(1) 29cm. long, immature. — Five distinct zones in otolith. It would 

 appear, therefore, that this fish would be at the end of its sixth year when 

 it began to spawn. 



(2) S4'7cm., immature. — Ovary very small, without yolked eggs. Four 

 complete zones in otolith, last one scarcely as wide as the others, but still 

 too wide to be considered the deposit of the season now commencing. 



(o) S7'5cm., immature. — Otolith shows five distinct zones, including, 

 of course, the central area. The fish, therefore, five years old. The fifth 

 zone is not quite so wide as the fourth. In the scales also five zones can 

 be distinguished, but not so certainly or clearly as in the otoliths. 



