BRITISH 

 FRESHWATER RHIZOPODA. 



[OWING to the discovery in Britain, since the first 

 volume of this monograph was published, of Arcellida 

 belonging to genera not then known to be represented 

 in this country, the list of British genera of the 

 Arcellida on page 37 of Vol. I requires revision. In 

 their sequence, also, some changes have been made, 

 and the list now stands as follows : 



A. ARCELLINA: (15) Arcella, (16) Pseudochlamys, (17) 

 Gen tropyxis . B . DIFFL UGINA : (18) Difflugia, ( 1 9 ) Pon ti- 

 gulasia, (20) Lesquereusia, (21) Phryganelld, (22) 

 Difflugiella, (23) Cryptodifflugia. C. NEBELINA : (24) 

 Hyalosphenia, (25) Nebela, (26) Quadrula, (27) Hele- 

 opera, (28) Leptoclilainys, (29) Cochliopodium, (30) 

 AmphizoneUa, (31) Zonomyxa. 



The same re-arrangement is also required in the 

 " Synopsis of the Genera" of the Arcellida on pp. 115 

 -117 of Vol. I, and the following diagnoses of the 

 genera now added are required to complete it : 



Test chitinous, compressed, smooth, usually with 

 foreign particles ; pseudopodia several, slightly rami- 

 fying, long and acutely pointed. 23. Cryptodifflugia. 



Test membranous, thin and supple near the mouth, 

 with a double marginal contour ; plasma uninuclear ; 

 pseudopodia digitate and blunt. 30. Ampliizonella. 



Test pellicular, supple, roundish pyriform ; plasma 

 granular, multinuclear ; pseudopodia simple, not digi- 

 tate. 33. ZonomyxaJ] 



VOL. n. 1 



