GO 



Guide io Cnisiact'a. 



Table-case IVont, or rosLrum, is not united with tlio epistome.. The sixth piiir 

 °- ^^- of abdominal appendages ( uropodsj are rarely absent. The last pair 

 of legs are reduced in size and the last thoracic sternum is movable. 

 The Sub-order is divided into three tribes, of whicli the first, 

 Paguridea, includes the Hermit-Crabs and their allies. With few 

 exceptions, the most important of which are the Coco-nut Crali, 

 Birgus, and the family Lithodidae, the members of this tribe have 

 the abdomen soft, not distinctly segmented, and sj^irally twisted in 



Fi(i. 3'J. 



The common Heumit-Crab, Kiipagiirnti bernhardus, in the shell of a 

 whelk, reduced. [Table-case No. 12.] 



adaptation to the habit of living in the empty shells of (lasteropod 

 Molluscs. 



The marine Hermit-crabs, forming the family Pdi/Kiuldc, nearly 

 all live in shells, and very often the outside of the shell gives 

 attachment to Sponges, Hydroid Zoophytes, or Sea Anemones, 

 between which and the Hermit there may exist more or less definite 

 relations of " commensalism." In the case of Pcif/uropsis ti/pica, 

 here exhibited, no shell is carried, but the abdomen is protected by 

 a cloak of living sea anemones held in position by the hinder 

 legs of the crab. The commonest British species, Eupagurua 

 hrrnltdrdtis (Fig. 39), and one of the largest representatives 



