62 



Guide to Crustacea. 



Tablc-L-ase Island, in the Indian Ocean, l)y Dr. C. W. Andrews, F.E.S., of the 

 Geological Department of the Museum, and. it shows a specimen 

 of Bir(/ns in the act of descending the trunk of a sago-palm. 



The memhers of the is,n'ii\y Li tliodidac have hecome completely 

 crah-like in shape, and were formerly classified with the Brachyura, 

 with which, however, they have no direct affinity. They may be 

 at once distinguished from the true Crabs by having only three 

 pairs of walking-legs visible behind the chelipeds, the last pair 

 l)eing carried folded up within the branchial chamliers. Their 

 relationship to the Hermit-Crabs is shown by the fact that the 



Fir;. 41. 



The " Noi'thei'ii Stone-Crab,"" Litltodos main, imich reduced. The last pair of 

 legs are folded out of sight in the gill chambers. [Table-case No. 12.] 



abdomen is frequently asymmetrical, and has appendages only on 

 one side. The last pair of abdominal appendages (uropods) are 

 wanting. 



The " Northern Stone Crab," Lilhodca niaiit (Fig. 41), found on 

 the more northerly coasts of the British Islands, belongs to this 

 family. Cri/jjlolllliodcfi is an aUied genus in which the carapace is 

 expanded at the sides so as to cover the limbs completely. A 

 specimen of the large EchidnoccriiH ciharitm found on the West 

 Coast of North .Xiiunicu is plucod in the lower part of Wall-case 

 No. 2. 



