PLAGIOPYXIS CALI.1DA. 47 



WAILES in Jrn. Linn. Soc., Zool. XXXII (1912), pp. 123. 131, 159; 



(1913), p. 212. 

 EDMONDSON in Ward & Whittle's Fresh-water Biology (1918), p. 22<>. 



f. 310. 



Test of medium size; grey, yellowish or brown in 

 colour ; ovoid with ventral side flattened or concave 

 and pierced by a linear, lunate aperture, the inner lip 

 of which is continued nearly parallel to the side of the 

 test for two-thirds of the distance to the crown ; 

 plasma limpid, grey in colour, containing numerous 

 small, pale, spherical granules and occasionally food- 

 particles of vegetable origin ; nucleus large, spherical, 

 with numerous minute nucleoles ; a single vacuole 

 occasionally present; pseudopodia numerous, radiating, 

 short, broad, pointed or palmate, very rarely observed. 



Diameter 55-135 /x, but usually 90-110 p. 



Habitat. Mosses. 



ENGLAND. Cumberland, Westmorland, and Lanca- 

 shire (Er oniii) ; N. Yorkshire ; Shropshire ; Bucking- 

 hamshire ; Cornwall ; Isles of Scilly. 



SCOTLAND. Elginshire (Brown}. 



IRELAND. Clare Island and Inishturk, Mayo ; Inish- 

 bofin, Galway. 



This is a widely distributed and often numerously 

 represented species ; the test is dark and opaque. 

 This, together with its narrowness, often renders the 

 aperture very difficult to locate. The pseudopodia 

 are so rarely observed that only once has their appear- 

 ance been recorded, a result achieved by Penard after 

 lengthy observations. The geographical range is 

 extensive, records extending to both the Northern 

 and Southern Hemispheres. 



Genus 18c. CUCURBITELLA Penard, 1912. 



Difflugia (pars) LEIDY Fresh. Rhiz. N. Amer. (1879), p. 114. 

 Cucurbitella PENARD Faune Rhiz. Leman (1902) 3 pp. 310-311. 



Test ovoid, not compressed, formed of variously- 

 shaped silicious grains ; aperture terminal, circular, 



