Here is a set of three belonging to the same animal, exhibiting with marvellous exactness the gradual development of a broken claw. In the first the member appears very diminutive, in the second it is nearly twice its size, while in the third it has advanced to its natural form and bulk. To my regret, I cannot state the exact period that elapsed between each successive moult, but I am confident that the trio were cast in the course of a very few months. I may here take the liberty of informing the uninitiated, that the appearance of the above objects is extremely pleasing; for, as the exuvium becomes dry, its colour changes to a bright scarlet, somewhat resembling that which the crab assumes when placed for a time in boiling water. The next series of specimens, five in number, possess even still greater interest than the first examples. They were produced by a youthful _C. mænas_, at the following consecutive intervals:-- The first moult took place on 11th April 1858; the second on the 22d of May following; the third on July the 3d; the fourth on the 30th of August; and the fifth on the 26th of September in the same year. So that between the first and second period of exuviation there was an interval of forty-one days, between the second and third forty-two days elapsed, between the third and fourth fifty-eight days, but, singular to state, between the fourth and fifth moult _only twenty-seven days intervened_. My first impression was, that as the creature grew older, its shell would be renewed less frequently, and the dates of the sloughings seemed to support this idea--until the fourth moult. It had occurred to me that perhaps the operation might be accelerated by the amount of diet which the crab consumed. In order to test this, I fed the animal carefully every day, as though he were a prize beast about to be exhibited at some Christmas show. Nothing loath, he ate of everything that was placed before him with a gusto that would have done credit to an alderman. The result was, that the shell was renewed in less than half the time that elapsed between the preceding moults. These interesting investigations, which had been conducted thus far so satisfactorily, were suddenly brought to a close by the death of my protégé. This sad event occurred unexpectedly, not from overfeeding, as some persons may suppose, but from natural causes. Whether increase of food always produces a like effect to that mentioned, is a point that I hope some of my brother naturalists will be able to determine. That the moult was accelerated by such means in my own specimen I have not the slightest doubt, for, on no other grounds can I explain its unusually speedy occurrence. I may here assure my readers that the above dates may be confidently relied upon as correct, and also that each exuvium was produced by the same crab--one specimen only being in the tank during the whole period.