PILL-MAKING CRABS.

New Zealand Graphic, Volume XVIII, Issue XX, 15 May 1897, Page 623

PILL-MAKING CRABS.

Mr Collingwood, in his ‘ Rambles of a Naturalist,’ gives an entertaining account of these tiny creatures, which are mostly of about the size of a pea, though a few are as large as filberts. He found them abundant on the shores of the Malay Peninsula his attention being first called to them by seeing the beach, after the going down of the tide, covered with loose, powderssand and holes of various sizes. Looking more closely, he discovered that little radiating paths converged among the litter of sand to each hole, and that the sand itself was in minute balls. The instant I approached, a peculiar twinkle on the sand was visible, which required a quick eye to recognize as the simultaneous and rapid retreat of a multitude of tiny crabs into their holes, not a single one remaining visible. Kneeling down and remaining motionless for a few minutes, I noticed a slight evanescent appearance, like a flash or a bursting bubble, which the eye could scarcely follow This was produced by one or more of the crabs coming to the surface and instantly darting down again, alarmed by my proximity. It was only by waiting like a statue that I could induce them to come out and set to work. Coming cautiously to the mouth of the hole, the crab waited to reconnoitre, and if satisfied that no enemy was near, it would venture about its own length from its lurking-place ; then rapidly taking up particles of sand in its claws, it deposited them in a groove beneath the thorax. As it did so a little ball of sand was rapidly projected as through its mouth. This it seized with one claw and deposited on one side, proceeding in this manner until the smooth beach was covered with little pellets, or pills, corresponding in size to its own dimensions. It was evidently its method ol extracting particles of food from the sand. I made many attempts to catch one before I succeeded. At last I caught two specimens, which immediatelv curled themselves up and feigned death. I put one of them on the sand to see what it would do. At first it did not attempt to move ; but after a little, by a twisting and wriggling movement, it rapidly sank into the sand and disappeared. The other one I put into a hole which already contained a crab ; but no visible result followed. I then attempted to dig it up again, but in vain. I dug up many holes ; but though I soon arrived at the soft wet sand underneath, I never succeeded in procuring a pill-mak-ing crab by digging it out.