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Show 502 PROF. J. E. DUERDEN OX CRABS [Dec. 12, carefully separate an actinian from its attachment (text-fig. 76). The crab moved round the actinian, inserting the tip of its limb at intervals, until in the end the polyp was dislodged, when it was seized and borne away. Text-fig. 76. 3felia tesseUata dislodging a fixed actinian by means of its first ambulatory limb. The crab Melia has thus the remarkable power of being able to detach a sea-anemone fixed to a substratum, proceeding in absolutely the same way as would a collector in endeavouring to secure the same kind of animal. Manifestly it is only by some such method that the actinian can be freed without injury, as the chela*, along with the other appendages, are almost useless as grasping-organs. In other instances where crabs mask themselves by hydroid, sponge, or algal growths the fragments are simply torn away by the chelipeds, but the dislodgment of an entire actinian without injury and without the use of the claws is an operation much more complex in character, whether we regard it as an instinctive or an intelligent act. When first grasped by the crabs the sea-anemones were not necessarily held in the most favourable position, that is, across the middle of the column with the disc directed upwards ; at the beginning the chelae seized them in almost any fashion, so that the disc and tentacles were directed at an angle. In one instance, an actinian which had been thus grasped in an irregular manner was turned towards the maxillipeds and there held in position by the first ambulatory limbs; the chela was then freed from the actinian, cleansed thoroughly, and finally seized the actinian so that it was held across the middle with the disc directed upwards. There seems some evidence also that the actinians themselves institute righting reactions, such as they carry out under more natural conditions ; so that, although at first grasped in any position, they are ultimately held across the middle with the |