316 



ZOOLOG r. 



It comprises the order of Merostomata represented at the 

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

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



Fig. 

 eize. 



i.—Cambarus peUuddas, the blind craw-flBh of Mammoth Caye. Natural 



wholly unlike that of other Crustacea, when we consider 

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



