154 
The Ovaries of Fishes. 
By 
J. T. Cunningham, M.A.. 
Naturalist to the Association. 
In connection with the inquiries which I undertook at the 
beginning of the present year into the question of the destruction 
of immature fish | have been investigating since the issue of the 
last number of the Journal the development of eggs in the ovary of 
some flat fishes and the history of the ovary before and after 
maturity is attained. I have made it my special object to trace the 
history of the ovary from one spawning period to the next, in order 
that it might be possible to understand more clearly than at present, 
from the appearance of an ovary examined at any given time, in 
what stage of development it was. Mr. Holt has made some 
observations on this subject, and discussed them in his paper in the 
number of this Journal for November, 1892. He states there that 
the first approach to maturity in the ovary is denoted by an 
enlargement of some of the ova, and the assumption by them of an 
opaque condition. He terms those ova which have begun to get 
opaque, “‘ active,’ and those which have not, “ inactive.” In a foot- 
note it is stated that the changes which give rise to the opaque condi- 
tion are not the same in all species, but that they appear to possess the 
same significance. Mr. Holt leaves undecided the question whether 
all the active ova are expelled during the spawning period, so that 
there is a period following the process of spawning when only 
“inactive”? ova being present, the condition of the ovary is not 
distinguished by internal structure from that of a fish which has not 
begun to breed, which is immature. He says that he has met with 
no such condition in the plaice, but that dabs presented such a 
condition in September after spawning about April. He says that 
when spent plaice are examined the ovary always contains a number 
of small active ova, in addition to a host of inactive, but he is 
uncertain whether the “active ” ova represent the early condition of 
next season’s crop, or only ova which, though they pass the inactive 
stage, are absorbed without becoming ripe. Mr. Calderwood in his 
paper on Fish Ovaries in the same number of the Journal dis- 
