136 Part ITL.—Twenty-third Annual Report 
In the coracoid four complete zones are visible, and an outer fifth, 
which is narrower. In the sub- and inter-operculum I can make out 
no distinct zones or boundary lines, 
(4) 50cm. (ubout 1 ft. 8 in.) mature, with ripe ovaries.—In the 
right otolith six complete zones visible and a peripheral seventh. I was 
in some doubt whether this last was the seventh annual growth in pro- 
gress, or whether it was really complete in the preceding winter and the 
eighth about to commence. The latter view seems more probable, so 
that this fish is seven years old. As it is far beyond the limit of size 
for immature plaice, it may have spawned either once or several times 
previously. 
The zones in the scales were rather difficult to distinguish, but there 
were apparently seven, including the central region and the extreme 
external zone. In the coracoid also there were visible six complete zones 
and a seventh at the periphery. The latter was narrower than the 
others, and opague, like the commencement ofa year’s growth. At present 
I do not know when the new growth commences, but in examining other 
specimens subsequently I have assumed that the outermost zone in 
specimens collected in March and April represents the last complete 
year, and not the commencement of the new annual growth. 
Heaps aNp PectoraL Reaions or PLAICE SENT FROM ABERDEEN, 161TH 
DeceMBER 1904: SEX NOT STATED, 
(1) 26:2cem. (104 inches actual measurement).—Otolith shows three 
zones, that is to say central area, complete second zone, and external 
zone. The fish is therefore in its third year; the third year would be 
completed some time in the commencement of next year. 
(2) 3L-2em. (123 inches actual measurement).—Otolith shows same 
condition, indicating that the fish is in its third year. If I understand 
him aright, this would be placed by Heincke in the second group, plaice 
which have lived two complete years and are in their third. In this 
case, the fish is larger than the maximum for this age of plaice on the 
Sylt grounds off the German coast (fig. 12). 
(3) 35cm. (14 inches actual measuwrement).—Otolith shows four com- 
plete zones, and a fifth at the margin. Same number could be made out 
in the scales, in the coracoid, and in the conical hollow on the faces of the 
vertebree (pl. viii., fig. 11 otolith, fig. 10 scale). 
(4) 37-5em. (15 inches actual measurement).—The otolith shows 
seven zones, including both the central area and peripheral zone. Accord- 
ing to this, the fish was in its seventh year (pl. vii., fig. 5). The first three 
zones are strongly separated, but the fourth and sixth boundary lines were 
much less distinct, and it seemed possible that they might be accidental 
and not annual lines, In this case, however, the fourth and fifth zones 
would be of disproportionate width, so that it seems more probable that 
the fish is really in its seventh year and not in its fifth. 
(5) 46°8em, (1S¢ inches actual measurement). — The otolith Be 
five zones, including the peripheral one. In this specimen I examined 
the hollow of the vertebral centra and the coracoid, and have figured 
them (fig. 14). In these also five zones can be distinguished, though the 
central area of the vertebral surface is scarcely visible, that is to say it is 
difficult to make out its boundary line. 
I also examined a large plaice 50 5cm. long, bought at a fishmonger’s 
in London last autumn. The otolith showed six zones. The fish was a 
mature female, and was therefore in its sixth year. 
—————— rl eel er 
