The moulting process being over, the crustacean’s body extends itself within the new, yielding skin; and, the latter becoming gradually hard by the deposition of carbonate of lime, the creature is able, after a period of rest, to roam at large again, without much fear of injury, until the time for the next moulting has arrived. Those who have made but a slight acquaintance with the common crustaceans of our shores must have noted the frequency with which imperfect specimens occur--specimens with missing appendages, or with a well-formed limb on one side of the body opposed to a puny and almost useless fellow on the opposite side. As to the loss of appendages, this matter will be readily understood by those who have watched crustaceans, and especially crabs and lobsters, in their native element, so often do these pugnacious creatures become engaged in furious broils with their neighbours. And, when we are at work at the collection of various species on the sea shore, how often do we find that a creature escapes from our grip by leaving us in possession of a severed limb, while the owner retreats rapidly among the stones and weeds apparently none the worse for its trifling loss! This is, in fact, a very common method of securing its escape from an enemy; and it appears that many crustaceans have the power of thus rendering a seized limb so brittle that it may be snapped off with the greatest of ease. We have spoken of the loss thus sustained as a trifling one; and so it is, for crustaceans have the faculty of reproducing lost appendages; and though the loss may be one of considerable inconvenience at first, a new limb eventually appears in the place of each one so willingly discarded. When such mutilations occur, it will be observed that the severed limb invariably breaks away at the end of the first or basal joint--a point where the bloodvessels are so narrow and contractile that but little loss of blood takes place when the rupture is made--and it has been said that the animal would soon bleed to death if the fracture were to take place at any other point. As it is, the wound soon heals, but no trace of a new limb is to be seen, at least without dissection, until the time of the next moult. The part is developing, however, beneath the cover of the basal joint; and when the moulting period arrives, the new limb, still very small, is exposed to view. It then rapidly enlarges, though not to anything like its proper size, and its surrounding skin becomes hardened by the deposit of the calcareous secretion simultaneously with that of the rest of the body. Further enlargements of the new appendage take place at subsequent moults, with the final result that it is but slightly inferior to its fellow either in size or in power.