313 
February 2nd repeated the experiment. One hatched in 
seven days and two hours, and on the 9th, having to leave 
Cheltenham, the remaining one was transferred to spirit, and 
the embryo was found to be alive. 
January 18th, placed three eggs in a tumbler of fresh water, 
changed daily. On the 26th all the others similarly treated 
with salt water being dead, these were returned to the trays 
and hatched in due time. 
January 28th, 11.30 a.m., placed two eggs in a tumbler of 
fresh water, and on February 7th, as they had not hatched, 
transferred them to the wooden tray, and they subsequently 
hatched. 3 
SIZE OF EGGS OF SALMONIDZ. 
We will now pass on to the eggs of Salmonide, premising 
that size is no criterion as to locality where ova are deposited. 
The Siluroid Ariine deposit their eggs, which are very large, 
in the salt water along the sea coasts. Those of the Arius 
are as large as any of the family, whereas the closely allied 
Bagrus, which deposits it in fresh water, have them very 
small, The carp genus Barilius in some species, at least, has 
large eggs, which is not the general rule in the carp family. 
If, however, we restrict ourselves to the eggs of the salmon, 
trout, and char, there is an excellent fieid for observation, 
respecting whether the size is in comparison with that of the 
mother ; if it is dependant on her age; whether local circum- 
stances affect it; and lastly, whether such have any influence 
on the future offspring. Many have written on this question, 
but not a few have simply copied the remarks of others, and 
thus erroneous opinions have been more prevalent than such as 
are simply exponents of well-ascertained facts. When this 
phenomenon is examined, it offers at least three distinct points 
for investigation. 1. Are the eggs of the Salmonide of one 
species invariably of the same size, or do they differ in 
accordance with the age of the parent? 2. Is there any differ- 
ence in the size of the eggs in two parents which are of the 
same age? 3. Can we detect any variation in the size of the 
eggs from a single parent ? 
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