VI 
INTRODUCTION. 
markings; another was black, with two bright ultramarine spots in the middle of the 
carapace; while another species was grey, marbled with white, with an enormous light 
yellow chela. These Gelasimi cover the ground by thousands, stalking about in a deliberate 
manner, and holding up and occasionally snapping the claws of their huge fore-legs. 
Notwithstanding that they appear to be over-burdened with this unwieldy member, they are 
by no means easy to capture, but run quickly to the mouths of their burrows, where they 
remain stationary, holding up their fore-claws as organs of defence, and, if fuither puisued, 
retreat backwards into their holes, their bodies protected by the same member. In the 
pools of fresh water and under damp stones, a dark olive-green Sescerma with bright yellow 
blotches was obtained, and on the coast numbers of the elegant and agile Thelphusa g rap - 
soides, which is found on the coral flats left dry by the receding tide. The Chasmagnathm 
convems of De Haan is another crab which appears to be rather common among the 
Philippine Islands. I have found it in the company of Xenophthalmus pinnotherides, in the 
firm black mud of Manila Bay, where it forms oblique cylindrical holes. 
Near the Dyak village of Samahrtan, not far from the mouth of the Lundu River in 
Borneo, there are certain mud-banks left dry at low-water, and which are perfectly cribriform 
with the cylindric holes of Gelasimi, Ocypode, and other genera. When their communities 
are no longer flooded by the water, these Crustaceans make their appearance in large 
numbers, but retreat on the slightest alarm into their subterranean burrows. They are of 
every variety of colour, some of them being milk-white, some purple, others reddish and 
mottled, while many are perfectly black. So numerous are these crabs, that seen at a little 
distance they give the surface a variegated appearance, nearly obscuring the original colour 
of the mud. 
In many parts of Borneo, as soon as the water recedes from the shore on the ebbing of 
the tide, and the large firm mud-flats are left exposed, numbers of Crustaceans of different 
genera and species issue from their various holes and hiding-places. The males of many 
species, after looking cautiously around them, stalk a few paces with their huge fore-legs 
raised, the claws of which they snap frequently together, producing a slight clicking sound, 
then rushing eagerly towards the females they embrace them with their fore-legs. The 
salute is very brief, and is immediately followed by the swift retreat of the females into their 
different burrows. Other species are seen feeding on worms and sliell-fish, feeding alternately 
first with one hand and then with the other. The common species of Grapsus varius is 
