CUCURBITELLA MESPILIFORMIS. 49 



The only British record is from a pond, where it 

 was found in the mud when the water was nearly dried 

 up ; in numerous previous gatherings from the aquatic 

 vegetation it had not occurred. The collar or peristome, 

 although usually four-lobed, is occasionally three-lobed, 

 and Leidy represents such a test on PI. xv, fig. 7. In 

 the United States individuals as small as 97 /u, in 

 length occur. Owing to the opacity of the test it is 

 not possible to examine the plasma in the living 

 animal. 



1. Pontigulasia rhumbleri Hopkinson. 

 (Plate LXIII, figs. 1 and 2.) 



Pontigulasia compressa 



RHUMBLER in Zeits. wiss. Zool. LXI (1895), p. 105, pi. iv, f . 13 a, b. 

 PENARD Faune Rhiz. Leman (1902), pp. 316-317, 3 figs. ; Sarcodines 



in Cat. Invert. Suisse (1905), p. 61. 

 AVERINTZEFF in Trudui S.-Peterb. Obshch. XXXI. u (1906), 



pp. 169-170. 



SCHOUTEDEN in Ann. Biol. lacustre, I (1906), 3, pp. 338, 339. 

 (Non Pontigulasia compressa Carter, 1864.) 

 Pontigulasia rhumbleri 



HOPKINSON in Cash's Brit. Freshw. Rhiz. II (1909), p. 162 (see also 

 p. 64). 



Test pyriform, compressed, formed of a chitinous 

 pellicle covered with diatom-frustules with a small 

 proportion of silicious grains; aperture elliptical or 

 sub-circular without any definite neck or constriction 

 of the test; internal diaphragm ribbon-shaped, widen- 

 ing towards the ends, placed centrally a short distance 

 within the aperture and attached to the broader sides 

 of the test; plasma partly filling the test; nucleus 

 single, placed near the f undus ; pseudopodia lobose, 

 long, numerous. 



Length 130 p. to 140 p ; greatest breadth about 

 three-quarters of the length ; thickness about half the 

 breadth. 



Habitat. Sphagnum and aquatic vegetation 

 shallow water. 



ENGLAND. Cumberland (Brown). 

 VOL. iv. 



