Note 13 — Chapter V · THE COMPARATIVE MORPH­OL­O­GY OF THE CRAY­FISH.—THE STRUC­TURE AND THE DE­VEL­OP­MENT OF THE CRAY­FISH COM­PARED WITH THOSE OF OTHER LIV­ING BEINGS.

The dimensions of crayfishes at successive ages given at p. 31, beginning at the words “By the end of the year,” refer to the “écrevisse à pieds rouges” of France; not to the English crayfish, which is considerably smaller. Doubtless, the proportional rate of increment is much the same, in the two kinds; but in the English crayfish it has not been actually ascertained.