THE SCAVENGERS OF THE SHORE 



pods of the bladder-wrack, which lay like green beads on the sand, 

 they fingered them with their blue-white hands, their claws, plucked 

 them to pieces, and conveyed them to their mouths, or dragged 

 their booty to their holes, so that in case of danger they could 

 disappear in a flash. 



If I made the slightest movement they were in their holes in 

 a moment, and it was some considerable time before they cautiously 

 ventured forth again. To catch them was impossible ; at least, I did 

 occasionally succeed in doing so if I sat motionless by a hole, waited 

 until the crab came out, and then, quick as lightning, flung a stone 

 over the hole. Sometimes, too, when wandering along the shore, 

 I caught a sand-crab who had ventured into shallow water in 

 order to moisten its chest-cavity, for the sand-crabs, like all their 

 kind, breathe through gills. The gill-chambers, which are enclosed 

 by the shell, retain the moisture for a long time, and when the 

 oxygen is exhausted the crab allows air to enter by a small aperture 

 in the rear of its body. 



If one disturbs the sand-crabs as they are wandering down to the 

 sea they run at full speed back to their holes. — In Ceylon too I 

 encountered sand-crabs; they were even more numerous than in 

 Brazil, and less timid, and fled back before the pedestrian like a 

 living wave. If they were brought to bay they reared up and lifted 

 their claws in a threatening manner, and a dog which used to 

 accompany me in Olinda did not dare to tackle so valiant an 

 adversary, but merely snapped at the air, barking, and prudently 

 keeping his distance. 



It always amused me to watch the sand-crabs, and I never 

 wearied of observing their apparently intelligent behaviour. I even 

 kept them in the house, in glass containers filled with sand, where 

 I fed them with insects. Here I was able to observe how the sand- 

 crab digs his hole. He presses himself sideways into the sand, grasps 

 a little pellet of sand with two legs and a claw, pulls himself back 

 with the four opposite legs, and then flings the sand away with 

 his claw. All this is done by jerky movements, and while the crab 

 is at work he keeps a constant and cautious watch upon his sur- 

 roundings. The hole, when finished, is so deep that one has to dig 

 for some time before coming to the bottom. The sand-crabs of 

 Brazil have certain relatives which live in a similar fashion, but 

 grow to a much larger size. The body of the sand-crab is seldom 

 larger than a five-shilling piece, but these other crabs are powerful 

 creatures, and their claws are as big as those of a large lobster. 



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