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Show 1905.] BEARING ACTINIANS IN THEIR CLAWS. 495 the manner in which the combination is brought about, and the peculiarities which each may exhibit in correlation with the commensal habit. The note by Mcibius is as follows:-" I have collected about 50 male and female examples of Melia tessellata, all holding in each claw an Actinia prehensa [text-fig. 72]. The hooks on the inner border of claws are bent in a peculiar manner, so as to hold fast the actinian. I have never been able to withdraw the actinian from the crab without injury. If the pieces of the actinian which had been thus withdrawn were allowed to remain in the vessel along with the Melia tessellata, the latter again seized them in a short time. If the actinians were cut into pieces they were again found in a few hours in the claws of the crabs. Text-fig. 72. Melia tessellata from Mauritius, holding an actinian in each claw (Richter). " It is very evident that the actinians by means of the threads of their stinging-cells are able to assist the crab in securing its prey, for which the actinian has the advantage of being carried from one place to another, and by this means is brought into touch with more animals which serve them as food. We have here a very interesting case of commensalism." Nothing further seems to have been contributed to this peculiar relationship between crab and actinian until Mr. J. Stanley Gardiner's expedition to the Maldive Islands. In the account of the marine crustaceans of this expedition, Mr. L. A. Borradaile (‘ The Fauna and Geography of the Maldive and Laccadive Archipelagoes,' vol. i. pt. 3, p. 250) writes of Melia tessellata (text-fig. 73, p. 496) as follows " The crab, which lives, like Trapezia, among the living branches of coral stocks, holding on by its long slender legs, has for some time been known to be in the habit of carrying in each chela a small sea-anemone. The object of this habit is not known, but it is certainly a voluntary act on |