124 BRITISH FRESHWATER RHIZOPODA. 



usually more or less ovoid, the surface covered with 

 numerous, short, hyaline, hair-like cils ; the aperture 

 terminal, of varying shape ; the plasma grey, granular, 

 not completely filling the test ; nucleus large, granular, 

 placed posteriorly; one or two contractile vesicles, 

 placed anteriorly ; pseudopodia long, numerous, 

 branching, but not anastomosing. 



Length 60-113 /a ; diameter about two thirds of the 

 length; cils 8-10 jx in length. 



Habitat. — Aquatic vegetation. 



England. — Isle of Wight ; Devonshire ; Cornwall. 

 Wales. — Dolgoth, Merionethshire (Gash). 

 Scotland. — Dumfriesshire. 



Ireland. — Armagh; Clare Island, Mayo; W. Galway, 

 Wicklow, and Kerr^ {Archer). 



Owing to the flexibility of the membrane the test is 

 somewhat variable in shape ; it is usually ovoid with 

 the aperture at the smaller end, but occasionally it is 

 found at the larger end; sometimes the test is of 

 nearly equal width for a portion of its length. The 

 hair-like cils with which it is thickly covered are 

 rigid and apparently of a chitinous nature; being 

 colourless and extremely fine they easily escape 

 observation. 



Large oil-like globules can often be discerned in the 

 plasma; they are readily stained by carmine. In the 

 larger individuals the nucleus is from 20 to 23 ju, in 

 diameter. Occasionally quartz-grains and diatom- 

 frustules are included in the foreign matter with which 

 the test is coated. Penard states that in some instances 

 he was unable to perceive the hyaline cils which usually 

 cover the test; these cils are unaffected by alcohol or 

 dilute sulphuric acid; they become invisible in glycerine 

 and Canada balsam. Double tests are occasionally 

 found. 



The long pseudopodia with secondary tuft-like 

 branchings depicted by Archer were only observed by 

 him ill individuals when first seen ; they were quickly 



