APPENDIX 247 



The gelasinus resembles the ocypoda in its habit of hole- 

 digging. It is a little red, yellow and blue crab with one of 

 its claws more developed than the other for the defence of 

 its threshold. Generally, the gelasinus prefers muddy beaches 

 to sandy ones, such as the flats which are subject to the tides 

 and the swampy terrain of the mangrove forests. 



On prevalently mud-bottoms, even in a foot of water, a 

 species of portunid is found. In form it is not unlike the small 

 crabs, Portunus holsatus and Portunus depurator of our own 

 waters, but it is much bigger than these. The cephalothorax 

 is extended transversally and ends in two sharp points. It 

 has long claws and its last pair of legs are spatuliform. It 

 uses these for throwing up clouds of mud. When in danger, it 

 lifts up its two claws parallel to its eyes, watches the enemy 

 and zig-zags to one side until it has disappeared in the 

 mud-screen. 



It is edible and in populated areas is sold in clumps by 

 fishermen in the streets. 



Decapoda anomura 



The anomura or hermit-crabs are numerically the most 

 diffused group on the coasts and among the islands of the 

 Red Sea. But they are the greediest, the most sociable, and 

 at the same time the most cruel of the Crustacea. 



The hermit-crab can in fact be classed a crustacean for 

 only half of its length. Its front half has antennae, claws, legs 

 and a cephalothorax, but the rear half, with its long, flaccid 

 abdomen, has, when danger threatens, to be pushed into the 

 empty shell of a marine gasteropod and sometimes even of 

 a land snail, just like a mollusc. In order to protect its 



