THE TAIL UNIQUE 387 



Acanthocope, Beddard, 1885, has the side-plates of the 

 pei'seon, except the first pair, furnished with long spine- 

 like processes, and the pleon ending in an elongate spine- 

 like process. The mandibles have a powerful molar and a 

 small, three-jointed ' palp.' The hind limbs of the perason 

 have a natatory character. The uropods are simple, long, 

 and stiliform, from three- to five-jointed. In Acanthocope 

 spinicavda, taken from a depth of 1,800 fathoms in the 

 Southern Ocean, the five-jointed uropods present a feature 

 unique in this tribe. Acanthocope acutispina, from South 

 America, has three-jointed uropods, and the first antennae 

 with a short flagellum instead of a very long one as in the 

 companion species. 



