40 ADDENDA. 



but I have thought that in one or two specimens of the ordinary form I have detected a 

 trace of the posterior median ridge. 



The approximation of this genus to Eumorphocoryistes of ]\I. Binkhorst is apparently 

 strcngtlicned by the occurrence of this specimen. 



In Mr. Carter's rich collection of Crustacea from the Cambridge Greensand, to which 

 I have been so largely indebted, are numerous specimens of fragments of limbs of the 

 greatest interest and beauty. T cannot but hope that before this work is completed fresh 

 investigations may enable us to appropriate some of these to species yet to be described, 

 and in this hope I have refrained from figuring or further alluding to them. 



