C 289 ] 
portion of fpawn I weighed in each cafe, I have fet 
down the number of grains in each fuch portion, 
in a fifth ; the number of eggs found in a grain, by 
this method is feen in a fixth, by which we may 
give fome gu.efs at the different fixes the eggs of each 
fpecies are of, when they are excluded ; and I have 
made the time of examining each fifih refpedlively a 
feventh ; which pofiibiy may be of fome ufe to thofe 
who may have an inclination to repeat any of thefe 
obfervations, as from thence may be learnt fomething 
concerning the moft advantageous time of examining 
thefe creatures, which certainly ought to be as nearly 
as we can, when the eggs are come to their full fize,. , 
and before any of them are depofited. However, after 
all, if my notion is juft, that fome fpecies depofit a 
part of their eggs come to their full growth, before 
others laid the fame year are big enough to be told 
with diftindtnefs, the accounts of the fecundity of 
fuch fi£h muff be extremely defective y and this I 
apprehend, amongft thofe I have examined, is the 
cafe of mackarel, carp, tench, and fome others ; in 
herring, &c. there does not appear fuch a difference in 
the fize of different eggs-. 
From this table it appears, that the fize of the eggs 
is nearly the fame in great and fmall fillies of the 
fame fpecies, at the fame time of the year ; that the 
quantity of fpawn is, ufually, nearly proportionate to 
the fize of the animal, from whence we may give a 
tolerable guefs at the greateft fecundity of each 
fpecies, if we know to what weight they have 
been found to grow while in a breeding ftate ; we 
may likewife fettle their produce at a medium,, 
upon learning what is the mean fize of each fpecies 
Vol. LVII. Pp when 
