EXPLANATION OF TLATES. 185 



PLATE I. 



Ceratiocaris armatus. 



fiG. 1. Ventral side of a specimeju, showing three segments, besides the terminal one, 

 with the tail-spines. 



«* 2. Dorsal side of tlie same, showing the spines at the posterior margins of the 

 annulations. 



*♦ 3. Ventral side of the terminal joint, and tail-spines, of another individual. 



Ceratiocaris longicaudus. 



Fig. 7. A fragment shov/ing the posterior joints of the abdomen, and tail-spines. This 

 figure is erroneously referred to in the text as fig. 4. 



«< 4, 5 & 6. Detached spines found in the same bed with fig, 7. 



Ceratiocaris? punctatus. 

 Fia. 8 The carapace of this peculiar crustacean. 



DiTHYROCARIS NEPTUNI. 

 Fig. 9. The terminal joir*t and tail-spines of this sj>ecies* 



[Senate, No. 115.] 24 



