At this period the young of the Decapods bear a strong resemblance to one another, whether they are afterwards to become long or short tailed crustaceans. After a time this creature loses its activity, moults, and is no longer to be recognised as the same, so great is the change (fig. 148, B). The dorsal spine has vanished, the shield has become flatter, its anterior part pointed, the eyes raised on stalks, and certain rudimentary organs that were below the eyes now form long antennæ. The first pair of feet have got hands, the others are jointed and simple, except the last pair, which are still natatory: with these and with the tail, which is now much smaller, these creatures swim and congregate round sea-weeds and floating objects. After the third moult they have the form of a crab, though neither that of the genus nor species of the parent (fig. 148, C). The tail is folded under a square carapace, the four pairs of walking feet spread widely and laterally, while the great hand-feet attached to the anterior sides of the carapace stretch straightforwards, the antennæ are short, and the eye-stalks bent to the right and left. It requires several moults to bring this creature to its final size and form.[38] Crabs sometimes die while moulting, and occasionally are unable to extricate a limb from its shell, and consequently lose it. But if a limb be fractured they can cast it off at the second joint, and soon after a diminutive limb is formed, which attains its full size at the next moult; but if the crab has not strength enough to cast it off, it bleeds to death. _Anomura._ The Anomura is a family of Decapods intermediate between the long and short-tailed Crustacea. There are nine or ten genera and many species, chiefly distinguished by the development of the head and thorax, and the softness of a non-locomotive tail: of these the Pagurus, or Hermit crab, is assumed as the type or representative.