120 BRITISH FRESHWATEIt EHIZOPODA. 



length ; few larger than this were recorded ; Penard 

 gives 17 to 71 /u, as the limits of length, remarking that 

 individuals over 50 ju, are rare. 



Small individuals sometimes occur with compara- 

 tively-smooth tests, and the collar may be a well- 

 defined beading around the aperture. 



The enlarged aperture with its collar of quartz-grains 

 renders this species easily recognizable among the 

 Pseudodifflugise. The test resembles that of Grypto- 

 diffliigia sacculus Pen. (length 20 to 40 /a) from which 

 species, however, it is distinguished by the longer neck 

 and more prominent collar around the aperture. When 

 active it is easily identified by the character of the 

 pseudopodia. 



5. Pseudodifl&ugia archeri Penard. 

 (Plate XL VIII, fig. 23 ; and fig. 154 in text.) 



Pseudodijflugia amphora 

 Penard (pars) in Kev. Suisse Zool. VII (1899). pp. 80-82, pi. viii. 



IE. 1-5. 

 Pseudodiffliigia archeri 



Pbnaed in Rev. Suisse Zool. IX (1901), pp. 231, 234, 238; Paune 



Rhiz. Leman (1902), pp. 456-458, 4 figs. ; Sarcodines grands Lacs 



(1905), pp. 57-59, 110, 115, 119, 125, 2 figs, on p. 68; Sarcodines in 



Cat. Invert. Suisse (1905), p. 92 ; in Rev. Suisse Zool. XVI (1908), 



pp. 462, 466. 

 Atbeintzbff in Trudui S.-Peterb. Obshch. XXXVI, ll (1906), pp. 



278-279. 

 Monti in Ann. Biol, lacustre, I (1906), pp. 130, 166. 

 ScHOTJTEDBN in Ann. Biol, lacustre, I (1906), p. 364, f. 35. 

 DOFLEIN in Sitzb. Ges. Morph. Miinchen, XXIII (1908), pp. 118-122, 



ff. 2-5. 

 Wailbs & Penard in Proc. R. Irish Acad. XXXI, lxt (1911), p. 19. 

 Wailbs in Jrn. Linn. Soc, Zool. XXXII (1912), p. 126. 



Test moderately large, of a dark colour, oviform, 

 covered with several layers of silicious grains ; trans- 

 verse section circular or broadly oval ; aperture ter- 

 minal, circular ; plasma grey, granular, often containing 

 numerous small crystals ; nucleus placed posteriorly, 

 large, granular, containing several nucleoles ; several 

 contractile vesicles and many vacuoles usually present; 

 pseudopodia long, numerous, straight or forked. 



