IN IDLE MOMENT 39 



the spider crabs, or Oxyrhynchus, most of which have 

 long horns projecting from the rostrum, and are more 

 or less thickly covered with stiff curled setae, to which 

 seaweeds, sponges, and other marine growths selected 

 according to the taste of the bearer are attached. 

 When these crabs shed their shells, which they must 

 do periodically to allow of growth, they retire to a 

 dark corner and draw themselves out of a slit between 

 the back and the abdomen, legs and all, which must, I 

 imagine, be a delicate and somewhat painful proceeding. 

 After emerging, they are, of course, quite soft, and the 

 setae on the carapace and legs are flexible. The crab 

 then selects choice bits of weed from its old shell and 

 fastens them to itself by the setae, which soon curl at 

 the tips like the tendrils of a vine, and so hold them 

 firmly. The weeds and sponges, requiring no roots, 

 but merely a secure base, readily grow in their new 

 position, and so cover their host with a sheltering 

 disguise, enabling it to sally forth in quest of fresh 

 loves and other adventures. I am sending the reprint 

 with the original description and figure, also a sketch 

 of the crab with its weedy garments. Much of the weed 

 had become detached on its arrival here, which is, 

 perhaps, fortunate, since the sketch would otherwise 

 have shown merely a cluster of weeds." It could be 

 well wished that the specimen had retained the whole 

 of its floral cloak, for then the sketch would have shown 

 its deceptive qualities in perfection. Masquerading as 

 a spray of seaweed, the crab eludes its enemies, the 

 mask being of such high order that even man, with his 

 perceptions, does not penetrate it unless he exercises 

 his reasoning faculties. Because he knows that a spray 

 of seaweed is not endowed with independent movement, 

 when it does walk about he, at first, is as incredulous as 

 was Macbeth when told of that "moving grove" of 

 Birman. 



