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is evidently convinced that they can probably be so explained. The 

 Xanthids are "Essentially crabs of the reef surface and the coral 

 stocks." A typical Xanthid, e. g. Xantho, "is of a transversely oval 

 shape, heavy and compact, with a hard cuticle and short legs which 

 can be folded up close under the body." "The massive, compact 

 form of the body and the strong cuticle are, no doubt, adaptations to 

 a life spent in positions where they are surrounded with hard stony 



others to enemies which they are unable to esc ape by swimming like 



the Portunidse Such genera as Chlorodius and Pseudozius are 



flatter and lighter built, with longer legs, though the cuticle is still 

 strong, and they are more often to be found in situations like the 

 interstices of coral stocks, where they must maintain their position 

 by the use of their limbs, rather than by their weight or by wedg- 

 ing themselves fast like the heavier genera." A bionomically inter- 

 esting species is Me/in tcsst //,,/</. Latr.. which lives among the living 

 branches of coral stocks. It holds in each claw a small sea anemone, 

 which would have to be dropped whenever the crab took food w ith 

 its chelipeds. "The actinians, which are firmly grasped around 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 purposes." The crabs of the subfamily Trapeziinae find shelter 

 on branched corals but only on the living branches. They do not 

 injure the latter but derive protection from their stinging cells. The 

 end joints of the rather slender legs are curiously modified to secure 



pools. Many of the 



