OVARIES OF FISHES. 157 
showing that the formation of yolk in the eggs for the next 
spawning season had begun by the time the present spawning was 
finished. This is the condition referred to by Mr. Holt on p. 369, 
Vol. II of this Journal, and he states that he was uncertain 
whether the yolked ova represented the early condition of next 
season’s crop, or only ova which remain undeveloped in the spent 
fish and are absorbed without developing further. The question is, 
therefore, whether the ripening of the eggs from the immature 
condition for the next spawning commences before the spawning of 
one season is concluded, that is to say, whether the development of 
the yolk takes a little more than, or less than the interval between two 
spawning seasons, 
Examination of other shotten fish, which of course became more 
numerous as time went on, showed clearly that no advance, but, on 
the contrary, a retrogression took place in them in the development 
of yolk. On February 2nd I examined a shotten plaice, 15} inches 
long, in which there were ripe but dead eggs in the cavity of the ovary. 
In the germinal tissue examined under the microscope there was a 
good deal of loose yolk from ripe eggs which had been broken 
during the spawning, but there were no small yolked eggs as in the 
specimen described above. 
On February 24th I examined a female plaice which appeared to 
be spent from the external appearance of the ovary alone. The 
right ovary was 3? inches long and the distance from the end of it 
to the end of the ventral fin 83 inches. In immature specimens the 
length of the ovary is always much less than this latter distance. 
The fact that it was a spent fish was placed beyond doubt by the 
presence of dead ripe eggs in the cavity of the ovary. Yet in the 
germinal tissue itself, when examined under the microscope, not a 
trace of yolk was to be seen in any of the eggs, the largest of 
which was ‘29 mm. in diameter. 
In March I examined no plaice, but in April several, some of 
which were evidently spent. On April 7th a specimen 142 inches 
long had a right ovary 23 inches long, and the end of it was 
43 inches from the end of the ventral fin. This fish might, from 
the size and appearance of the ovary, have been set down as 
immature, but in the stroma, under the microscope, could be seen 
here and there shrivelled remains of yolked eggs, much fewer in 
number than the yolked eggs in spent ovaries previously seen, but 
evidently of the same kind, and suggesting clearly that the ovary 
was spent, and reverting to the yolkless condition. Another 
specimen of the same size, examined on the same date, had the ovary 
in a similar condition, but the degenerating ova were still fewer in 
number. The size and external appearance of the ovary in these 
