250 L- A. BORRADAILE. 



18. Melia tessellata (Latr.) (Fig. 49.) 



Melia tessellata, Borradaile, Pi-oc. Zool. Soc. 1900, p. 580. 



This 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 the part of the crab, for the actinian is not attached, but held between 

 the fingers of the Melia, and, if it be taken away, will be again seized. Usually there is an 

 anemone in each hand, but sometimes one or both hands are empty. The actinians, which 

 are grasped firmly round the middle below the tentacles, may be useful, by means of their 

 stinging-cells, either for defence or to " fish " for food with, or perhaps for both purjjoses. 

 The chelipeds 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 thovigh 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 ft-inged with long hairs. 

 Possibly they are used to catch small organisms for food in much the same way as those of 

 the China Crabs (Porcellanidae), 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, what- 

 ever its use, it cannot be a means of passive concealment, to which its size is wholly inade- 

 quate-. 



Melia tessellata is not recorded from the Indian region by Alcock, who finds the genus 

 represented there by two quite distinct new species {M. caesti/er and M. pugil). It would be 

 interesting to know the precise distribution, geographical and habitative, of these three species. 

 The " hairs " mentioned by Alcock as found on the fingers of his new species may possibly 

 be the remains of actinians, rotten from bad jjreservation, and in that case it would be needful 

 to determine whether each species of crab has its own species of anemone. Of course we 

 must also know whether the latter be full grown or only young individuals. The species was 

 taken on the reef in Male, Addu, Minikoi and Goifurfehendu Atoll. 



Subfamily Xanthinae. 

 Genus Cymo de Haan, 1833. 

 The members of this genus live under stones, in coral blocks, etc. 



' The fact was noted in 1880 by Richter (Mobius' Meeres- ments to fasten together the edges of the leaves which form 



fauna Mauritius), but since then its interest, and indeed its its home, holding them, the while, in its jaws. There is also 



Tery existence, have been generally overlooked. said to be a wasp which uses a stone to beat down the earth 



^ The aut Oecophylla smaragdina uses its own larvae over its burrow, 

 (which haTe glands for making a cocoon) as spinning imple- 



