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 Mobius is as follows:—‘“‘TI 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 ac- 
tinian which had been thus withdrawn were allowed to remain in 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 Lacca- 
dive 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 
