478 D. W. CUTLER. 
end of the tail, and the third the number of annual rings which the scale 
exhibited. The figures in brackets are the number of sclerites produced 
towards the last and incomplete annual ring. In the fourth column is 
noted the number of sclerites formed during each year’s growth. 
The first point of interest arising from this table is the great variations 
in length that occur between fish of almost the same age ; thus the length 
for second year fish varies from 7°9 to 9°6 cm., increasing as the fish enters 
on its third year of life, so that in one case a fish of 25°5 em. in leneth 
was found to be but 2? years old. Again, I have enumerated fishes in 
their third year of life with lengths, 15°5 em., 25 cm., 27°3 cm., and 32:1 
cm. respectively. 
It is true that in the normal conditions there would in all probability 
not be these enormous differences in the lengths of fish of the same age, 
because the external conditions would be more or less uniform for the 
fish of the same district. This condition has not been fulfilled, for a few 
of the animals in the Table, for experimental reasons, have been sub- 
jected to temperature variations and changes in the amount of food. 
In many cases, where the length is great in proportion to the age the 
animals have probably received more food than one would expect them 
to get from their normal habitat. 
A further point to be observed is that the number of sclerites formed 
in the scale seems to be correlated with the condition and length of the 
fish ; thus of the third year fish, marked +, the one 15°5 cm. long had 
but 28 sclerites, while of the others those with lengths 32 cm. and 32:1 em. 
had 62, and 75 sclerites respectively. The three fish selected exhibit this 
phenomenon very clearly, but in practically all cases the same condition 
obtains. Thus I feel that I am right in stating that on the whole the 
sclerite formation and the growth in length are correlated. 
J. Stuart Thomson, in his paper on the scales of the Gadide (p. 74), 
comes to the conclusion that intensive growth favours the production 
of a small number of sclerites. 
To illustrate this he takes the case of a pollack three years of age and 
27°62 cm. in length. Examination of the scales showed the following 
number of sclerites for each year: year1,13; year, 13; year 11, 18. 
From this he goes on to say: “‘ We have evidently here to deal with a 
rapidly grown fish, and this fact has expressed itself in the formation of 
the scale, in the small number of lines of growth for the first and second 
year. The more intensive the growth the smaller the number of the lines 
of growth. To compare with this we might take the case of a slower 
growing pollack, 44-40 em. The scale of such a pollack shows the follow- 
ing lines: year 1, 21; year m, 29; year 11,18; year Iv, 2.” 
I do not quite understand this statement because, according to 
Thomson’s Table, the first fish mentioned, of length 27°62, was small 
