122 EAMBLES OF A NATUEALIST. [Oh. Till. 



all their colour. Fine specimens of the barnacle, Pollicipes 

 mitella, were wedged in clefts of the rocks ; and running 

 about hither and thither upon them were numerous active 

 crabs, of the genus Grapsus, which are more or less charac- 

 teristic of aU tropical islands. They are somewhat quadri- 

 lateral in form, and have a flattened aspect, and are so wary 

 that it is a most difiicult task to capture them, more par- 

 ticularly as they are always found upon irregular, and often 

 smooth rocks, over which they run with great velocity, in 

 places where it is impossible for their pursuers to find a foot- 

 ing. The first pair of legs is short, curved, and spinous the 

 other pairs usually more or less compressed, and hairy to 

 the extremity. With these they hold securely to the most 

 slippery surfaces. The most generally distributed species 

 is one (G. strigosus) ornamented with long wavy lines of 

 red and orange, and a very beautifully marked animal. Their 

 cast shells of all sizes strew the rocks in all directions, 

 and are scarcely distinguishable from the living animals, 

 except that, perhaps, the tints are less vivid than those of 

 the living ones. When taken up, however, they fall to 

 pieces, unless great care is used. It was amusing to watch 

 the Grapsi, which always seemed to know when they were at 

 a safe distance, and then did not trouble themselves to 

 move ; but stir a foot, and they would scuttle away in all 

 directions, and, if closely pursued, escape into crevices, or 

 down gullies between the rocks, where it was impossible to 

 foUow them. I have seen these crabs not only move up and 

 down nearly perpendicular surfaces, when midisturbed, but 

 leap sideways over crevices several inches wide, a feat which 

 they performed with singularly little effort, and so rapidly as 

 scarcely to attract observation. 



But my time was too limited to allow of my doing more 



