NOTES ON CERTAIN SHORE CRABS. 309 
of carrying the arm folded closely to the body, as is usual 
on entering the burrow, in this case carried it trailing behind. 
Tennent, in his ‘‘ Natural History of Ceylon,” says that these 
crabs, presumably Gelasimus annulipes, are common on the 
sandy shores north and south of Colombo. I have not found 
any in the immediate neighbourhood of Colombo, but there 
is a colony to be seen on the island opposite the resthouse 
at Negombo. 
Dotilla—This species, which I have identified as Dotilla 
mycteroides, is not so striking in appearance as the last 
one, but in its habits it is more interesting. It is of a dull 
brown colour, rather globular in form, and is provided 
rather long arms of equal size with long pointed fingers. It 
inhabits the fine, rather dry sand nearer the sea than the 
Gelasimus. Its burrows are of much the same form, though 
smaller, are usually covered at high tide, and thus have to be 
partly re-made after each tide, as in the case of the others. 
The diagram (Fig. 2) shows the surroundings of one of the 
burrows of a Scopimera crab, which closely resemble the 
runways of the Dotilla. These crabs are comparatively tame, 
and as they are small, the best way to watch them is to sit or 
lie down in the middle of a colony. They will soon emerge, 
and may be watched at a distance of a few inches if the 
watcher remains absolutely still. The most noticeable 
feature of the colony is a series of “‘ pathways” leading to 
little holes, with heaps of countless little round pellets of 
sand at one side (occasionally both sides). When the tide 
has gone down leaving the sand quite smooth, the crab, from 
inside, breaks open the entrance to the burrow and emerges, 
at once starting to feed; at first there is no sign of a 
pathway, and no sign of balls of sand, the feeding crab making 
both as it feeds. As in the case of the Gelasimus, this 
crab appears to live entirely upon fine particles of food which 
adhere to the sand. Thus, in order to feed, the crab squats 
down and starts shovelling sand up to its mouth with the 
two long “‘hands” alternately. In this case, as opposed to 
the habit of the Gelasimus, the sand passes into the mouth 
from below and emerges above to form a sort of ball or pellet, 
which is held in position by the maxillary palps which extend 
16 6(5)20 
