HOW CKABS PUT THEIR CLOTHES ON 113 



faction of seeing how the crab slowly stepped up to the 

 polyp-mass, and with its claws tweaked off small points of 

 the branches. At first it let them lie on the floor of the 

 aquarium, but later on fished one of them up again with 

 its claw, which it bent over the back of its carapace, and 

 there among the fur it planted the fragment of the polyp 

 with the severed surface downwards ! 



Further experiments showed that not only in the species 

 of Maia, but also in those of Pisa, Macropodia, Inaclms, and 

 other Oxyrrhyncha, the foreign organisms were fastened to 

 the crabs' bodies by the crabs themselves. That the object 

 was concealment by the wearing of a mask was obvious, 

 since the costuming was never at random, but always in 

 strict agreement with the surroundings. Moreover, these 

 marine zoologists know what sponges and polyps can be 

 chopped up without causing mortality in the fragments. 

 The pieces they plant are pieces that will live and thrive, 

 and, as Dr. Graeffe observes, the keepers of aquaria have 

 only to consult the crabs to learn what kinds of sea- 

 animals will bear being thus transplanted piecemeal. For 

 keeping on their living mask Dr. Graeffe found that the 

 natural coats of these Crustacea were furnished with hairs 

 varying in arrangement and shape in the different genera 

 and species, some of the hairs being fish-hook-shaped, 

 others clubbed, and others simply tapering, but all more 

 or less serrate, the simple ones sufficing to detain a coating 

 of slimy mud, while the others hold captive the living 



organisms. 



Dr. Graeffe published his observations in 1882, but 

 already in 1878 Dr. Eisig had reported of a species of 

 Inachus that he had seen it plucking Hydroids and plant- 

 ing them on its spines and hairs, and Dr. C. Ph. Sluiter in 

 1880, when establishing the new species Chorinus -alc/atec- 

 tus, described its way of spitting little fragments of algas 

 on the strongly bent booklets of its body and legs, to mask 

 itself from its enemies and its prey. Additional details of 

 great interest were published in 1889 by the Swedish 

 naturalist Dr. Carl W. S. Aurivillius. 



Hyas, Leach, 1813, comprises but few species, two of 



I 



