THE VIOLET FLAT-CRAB. 
249 
which communicate with the sea by means of creeks, 
the tide running in and flooding the morass, or run- 
ning out with as rapid a stream and draining it. On 
the roots and up the trunks of the Mangroves, the 
Flat-crabs may be seen crawling by thousands, mov- 
ing with exceeding deliberation if unexcited, but if 
need be, darting up, or down, or round the tree, as 
swiftly as a lizard. This at once attracts notice ; 
for we are apt to think a crab’s feet not the most 
adapted for climbing, and perhaps have wondered 
at the accounts given of the Tree-lobsters {Birgus), 
of the South Sea Islands, which are said to rob the 
cocoa-nut trees. With our Flat-crab, however, it is 
a matter of constant occurrence ; he runs up any 
perpendicular surface, not hy grasping, but on tiptoe, 
as he runs on a level, not making much use of the 
claws, though these occasionally aid the progression. 
Sometimes when watching for birds, seated on one 
arching root, with my feet on another, remaining 
quite still, with my fowling-piece across my knees, 
I have been entertained by observing the manners of 
these pretty Crabs. When the tide is out, the water 
collects in little pools, particularly near the margins 
of the morass ; and in and about these pools the 
Crabs are crawling, seeking for food. The manner 
in which they pursue their search is curious, and 
seems to indicate a sensibility of touch in the hard 
and stony points of the claws, which we should not 
expect to exist there. 
The Crab crawls slowly along, in no defined di- 
rection, while the two claws are held, points down- 
ward, in front of the face, and lightly feel the surface 
M 5 
