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 Eumorphocorystes of M. Binkhorst is apparently 

 strengthened 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. I 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. 



