Measurements of Crabs

Abstract

I AM much obliged to Prof. Weldon and Mr. H. Thompson for the careful consideration they have given to the doubt which I raised concerning the validity of the comparison made by the latter of measurements of crabs collected from the same locality in different years. Prof. Weldon offers some evidence to show that immersion in spirit does not affect the relative dimensions of parts of the carapace. The evidence is not direct, nor perhaps is it complete. It refers to female crabs, and not to the male specimens with which Mr. Thompson was dealing. But I notice that according to Prof. Weldon's measurements the spirit specimens of 1895 differed more than the fresh specimens of 1895, from the spirit specimens of 1893, whereas if the spirit were the cause, the difference would be less between spirit specimens and spirit specimens than between spirit specimens and fresh specimens. I admit then that there is little possibility of the observed difference being due to the action of spirit.