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Show 1905.] BEARING ACTINIANS IN THEIR CLAWS. 4 9 7 are slender and feeble-ill-suited for defence, but at the same time mobile and well adapted to wield the anemones they carry ; and, if the crab be threatened, it will stretch out its arms towards the aggressor, as though it would ward him off with the disagreeable obstacles it thus presents to his attack. Certainly the fingers cannot be used to take food unless the anemone be first dropped ; but, on the other hand, the tentacles of the latter are directed outwards, away from the mouth of the crab. The third maxillipeds are mobile, with the proximal joints rather slender and the last three stout, and are fringed with long hairs. Possibly they are used to catch small organisms for food in much the same way as those of the China Crabs (Porcellanidte), which part with their chelipeds so readily when they are attacked, since they do not use them for taking food. " In any case we seem to have here an interesting example of the use of an implement by an animal which, however intelligent, has at least a very differently organised nervous system from the Vertebrata. It should be noted that the case is different from that of a Spider-crab, which sticks pieces of seaweed on its back and enjoys passively the concealment gotten thereby. For the Melia carries the anemone in its cheliped-the chief grasping-organ of the animal, corresponding to the hand of a primate or the trunk of an elephant-and, whatever its use, it cannot be a means of passive concealment, to which its size is wholly inadequate." These two accounts leave much to be desired ere we can be said to have a complete acquaintance with the living relationships between Melia and its associated actinians, and their peculiarities of habits and reactions. A short time ago Miss M. J. Rathburn, of the United States National Museum, forwarded me for identification the actinians held in the claws of a specimen of Melia. The crab had been collected at Hilo Bay, Hawaiian Islands, by Prof. Henshaw, and the actinian proved to belong to a species of Bunodeopsis, a genus wTell known as occurring in the Mediterranean and the West Indies. During a recent visit by the author to the Hawaiian Islands, under the auspices of the Carnegie Institution, for the purpose of studying the living corals, an effort was also made to procure other specimens of Melia and its commensal actinians. On the second day's collecting over the reef-flats at Waikiki Beach, near Honolulu, a single crab carrying actinians (text-fig. 74, p. 498) was obtained, and another a few days later. During all the subsequent collecting, extending over three months, at various points of the islands, no other Melias were seen, so that evidently the species is not so common in Hawaiian waters as in the regions visited by Mobius and Borradaile. Both specimens of Melia were found on the dead under surface of coral blocks, not wandering among the branches of the living-coral as in Borradaile's experience. Further, Prof. Henshaw, who has on rare occasions collected the crab at Hilo Bay, also |