THE DEC APOD A 



261 



coiled to fit into the Gasteropod shells inhabited by the animals. 

 Only the sixth somite and the telson are fully calcified, the tergal 

 portions of the other somites being merely indicated by widely 



& 



Fio. 151. 



Pylochdes Miersii (Paguridea). a, end view of the animal lodged in a tube of water-lc 

 mangrove or bamboo, its chelipeds closing the opening. The lower figure shows the ar 

 in a conventional attitude after removal from its refuge. (From Alcock, Naturalist in Indian 

 Seas.) 



separated chitinous plates in the membranous investment of the 

 dorsal surface. In the coco-nut crab Birgus (Coenobitidae) (Fig. 

 152), which has abandoned the use of a covering for the hinder 

 part of the body, the abdomen, though short, is symmetrical 

 and its terga are well calcified. In the Lithodidae (Fig. 153), 



