HOW CRABS 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, Inachus, 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 suflicing 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 algatec- 
tus, described its way of spitting little fragments of algze 
on the strongly bent hooklets 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. 8. Aurivillius. 
Hyus, Leach, 1818, comprises but few species, two of 
