64. H. W. MARETT TIMS. 
The same idea has also from time to time been referred 
to by other writers. During the course of my observations 
I have been led to note carefully the appearance of the scales 
endeavouring to estimate the ages of the fish with whose 
scales I was dealing, and the length of which only was known 
to me. In young fish the rings are quite easily to be recognised, 
which Thomson regards as the rings of growth of the first 
summer and first winter. Such a scale he figures in his paper. 
It may be noticed in passing that the point of the first 
bifurcation of the lines of scalelets at the one pole marks 
what Thomson regards as the period of first summer growth, 
and that the further bifurcation previously mentioned as 
being present in some scales corresponds with the limit of 
first winter growth. ‘This is about the farthest point to which 
Iam able to follow. With the increasing size of the scale, 
I confess Iam quite unable to detect that regular series of 
alternating broad and narrow bands such as Thomson 
describes. From the scale of a G. Callarias 24 feet in 
length, one of which is represented in fig. 6, I cannot make 
any estimate as to the age. If this be so in the cod, I find 
still greater difficulty in the case of the herring and other 
Clupeoids, concentric markings upon which are not merely 
irregular, but to many the term “ labyrinthine” might almost 
be applied. Asa method of practical value, it seems to be of 
but little value, at any rate in my hands. 
Apart from this, however, there seems to be many theo- 
retical objections. Klaatsch and others have pointed out 
that the scales do not appear simultaneously all over the body. 
‘hey commence to appear just behind the pectoral fins in the 
neighbourhood of the lateral line. From this point the appear- 
ance of the scales radiates, those in the tail region being last 
to appear. It appears, therefore, that in instituting com- 
parisons of age, the scales should always be taken from the 
same region, and that region stated. Of course, if the exten- 
sion of scales over the whole surface of the body is rapid, then 
the limit of error will be so small as to be practically neglig- 
ible. Until we have some data as to the rate of extension 
