318 GAMMA RID^. 



ters of N. aqvilex^ however, given by Schiodte, which 

 we have verified and introduced into our specific cha- 

 racter, in addition to the remarkably beautiful series of 

 details of N. stygius published by Schiodte, leave but 

 little doubt in our minds of the correctness of his views 

 in considering the Maidenhead specimens as belonging to 

 a distinct species. 



In addition to the Maidenhead locality mentioned 

 above, we have received a specimen captured at Wands- 

 worth, Surre}^, from Mr. W. W. Saunders ; also from 

 Mannamead, near Plymouth (where the long and short 

 tailed specimens , are associated), and have taken it in 

 pump water at Leyden, where also Dr. Herklots has 

 taken two specimens (preserved in the Leyden Mu- 

 seum); Caspary found it abundantly at Elberfeld ; 

 Hosius at Bonn ; the Baron De la Vallette St. George 

 in a well at Cologne in considerable numbers in Novem- 

 ber and December ; Correnzio at Munich ; and Koch 

 obtained it from the draw-wells about Zweibriicken. 



Koch's figure of the animal is coloured of a pale 

 greenish grey ; but Mr. White says, in his History of 

 British Crustacea, that it is snow-white. 



