igo THE LIFE OF CRUSTACEA 



The Gecarcinidae are abundant in the tropics of 

 the Old and New Worlds. Some of the species at 

 least, probably all, visit the sea at intervals for the 

 purpose of hatching off the eggs carried by the 

 females, and the larval stages are passed in the sea. 

 In the case of Gecarcinus ruricola (Plate XXVI.), a 

 species very common in the West Indies, the migra- 

 tion to the sea takes place annually during the 

 rainy season in May. The Crabs are described as 

 coming down from the hills in vast multitudes, 

 clambering over any obstacles in their way, and even 

 invading houses, in their march towards the sea. 

 Stebbing states that " The noise of their march is 

 compared to the rattling of the armour of a regiment 

 of cuirassiers." The females enter the sea to wash 

 off the eggs which they carry attached to their 

 abdominal appendages, or rather, probably, to allow 

 the young to hatch out. The Crabs then return 

 whence they came, and are followed later by the 

 young, which, having passed through their larval 

 stages in the sea, leave the water, and are found in 

 thousands clinging to the rocks on the shore. 



On Christmas Island, in the Indian Ocean, 

 Dr. C. W. Andrews studied the habits of another 

 Land Crab, of which the proper name seems to be 

 Gecarcoidea lalandii. He says : " This is the com- 

 monest of the Land Crabs inhabiting the island, and 

 is found in great numbers everywhere, even on the 

 higher hills and the more central portion of the 



