296 ZOOLOGY. 



It comprises the order of Merostomata represented at the 

 present day by the king-crab, and the order Trilobita, which 

 IB wholly extinct. The organization of the king-crab is so 



Fig: 2G3.Camba.ruspellucidus t the blind craw-fish of Mammoth Cave. Natural 

 Size. 



wholly unlike that of the Crustacea, when we consider 

 the want of antennae, the fact that the nervous system is 



