86 OUR CARCINOLOGICAL FRIENDS. 
the ambient waters, for they appear to delight in 
the mud-flats as much as the other species; but 
they possess, in the art of swimming, one advan- 
tage over their fellows. 
When the embryo crab escapes from the egg it 
is liberated in the form of a very remarkable little | 
body known as the Zoea, whose real nature was for 
-—— 
ZOEA OF CRAB (magnified). MEGALOPS (magnified). 
a long time a sealed chapter to the naturalist. This 
Zoea is furnished with a big head and an elongated 
body, but the features that most readily arrest one’s 
attention are the three or four long spines which 
appear to be carelessly thrust out from different 
parts of the body and head, and which give to the 
tiny creature a singularly uncouth aspect. For 
many years before the connection between the Zoea 
and the crab was known, the former was looked 
upon as a mature animal, and naturally regarded 
as a distinct species. From the Zoea the crab 
passes by gradual stages to the Megalops con- 
dition, when, as the name indicates, the eyes are 
developed to a disproportionately large size. In 
this process of growth to maturity the crab is com- 
pelled at repeated intervals to cast its skin or shell, 
