258 THE INHABITANTS OF THE SEA. 
of a long articulated tail the restless Chimera continually turns 
head over heels. Claws are wanting, and while the old crab is 
of course a perfect decapod, the young iias only four bifid legs, 
armed at the extremity with four long bristles, that are con- 
Metamorphosis of Carcinus mcenas. 
A. First stage. B. Second stage. C. Third stage, in which it begins to assume the adult form. 
D. Perfect form. 
tinually pushing food towards the ciliated mouth. Who could 
imagine that a creature like this should ever change into a crab, 
to which it has not the least resemblance? But time does 
wonders. After the first change of skin the body assumes 
something like its permanent shape, the eyes become stalked, 
the claws are developed, and the legs resemble those of the 
crab, but the tail is still long, and the swimming habit has not 
yet been laid aside. At the next stage, while the little creature 
is still about the eighth of an inch in diameter, the crab form 
is at length completed, the abdomen folding in under the 
carapace. No wonder that these larvee were long supposed to be 
distinct types, and described under the 
v \ names of Zoéa and Megalops, until 
ZioowWN ~\\ Mr. T. J. Thompson first discovered. 
their real nature. 
The life history of the Palinuri or 
spiny lobsters is equally curious. They 
vee ea frequently weigh ten or twelve pounds 
each, and are distinguished. by the very large size of their 
lateral antennee and by their feet being unarmed with pincers. 
Surely nothing can be more dissimilar than the glass crabs or 
