134 



INVERTEBRATE ANIMALS. 



owra^ tail), from the fact that the end of the abdomen is 

 furnished with a long sword-like spine (Fig, 53, <). The 

 mouth is surrounded by six pairs of appendages, the bases of 

 which are spinous and act as jaws, while their free extremities 

 are developed into nipping-claws or chelae. The whole of the 

 upper surface of the body is protected by a kind of buckler, 

 composed of an anterior semicircular shield, and a posterior 

 somewhat hexagonal plate, the under surface of which carries 



Fio. BS. — Xiphosura. lAmiiJMS poly- 

 phemua, viewed from below. 



Fig. 54. — Eniypterida. Pterygoiut 

 Angliffus^ restored (after H. Wood- 

 ward). 



branchial plates, while the sword-like telson is jointed to its 

 hinder margin. The king-crabs attain a large size, and are 

 often called " Molucca crabs " from their occurrence in the 

 Moluccas. Both the eggs and the flesh are eaten by the 

 Malays. 



Closely allied to the king-crabs is the extinct family of the 

 Eurypterida, an example of which is figured above (Fig. 54). 

 This species is supposed to have attained a length of probably 

 six feet, but other forms were very much smaller. 



