55 
With these considerations in mind I have indicated alongside 
Chart VIII. the number of years which may be supposed to be 
necessary for the growth of such a crab, and I have in Chart IX. 
expressed the growth of this crab. I do not venture to suggest 
that it conveys an absolutely correct picture of the growth 
of the crab, but I offer it as an indication of Crustacean growth in 
general, based however on the facts so far as we possess them for 
the crab, Cancer pagurus. 
The female has been particularly considered in arriving at the 
above conclusions, but the male is evidently liable to the same laws 
of growth, and, although it is probable that the rate of growth is 
greater in the case of the male, it is not at all likely either that the 
male casts regularly every year after maturity is attained. It must be 
remembered that the growth is subject to a great deal of variation, 
both of external and internal origin, and, from what has already 
been said with regard to the difference between the North and South 
divisions of the County, it may be inferred that the rate of growth will 
be on the whole somewhat greater in the northern district. 
Another point deserves to be pointed out, and it is that the 
sperms of the crab may remain in the spermathec® of the female 
for two or three months more than one or two years, and perhaps in 
the case of the larger females for over three years, before being used 
for .the fertilization of the ova. 
In my previous unpublished- attempt to state the growth of the 
crab I had the privilege of analysing the carefully measured series 
which Williamson collected at Dunbar, the details of which he has 
since published*. I beg to take this opportunity of thanking him for 
his kindness in letting me have the use of his table, and I may be 
allowed to add that the conclusions arrived at then were not very 
different from what have been stated above. 
The female crab may become mature at a size of 4| inches, but 
she usually measures 5 or 5^ in. before spawning. It is probable 
therefore that the female crab is five years old at maturity. 
The following table gives the measurements of the ecdysed 
cuticles referred to. Only a few convenient measurements have 
been made with a view to stating some of the facts of regional 
growth. In the case of the chela the columns headed 1 and 2 refer to 
the measurement (1) of the external border of the dactylopodite and 
(2) of the internal border of the propodite^ 
* 22nd Rep. S. F. B,, 1904; 
