PSEUDODIFFLUGIA HORRIDA. 119 



tests of Rhizopoda, but may be only intruders in most 

 cases and not truly parasitical. 



The plasma of P. horrid a can only be examined by 

 expelling it from the test, which is covered by a con- 

 fused mass of diatoms, grains, and silicious plates ; the 

 colour as a whole varies from brown to nearly black ; 

 the aperture appears flexible and may be found entirely 

 closed or widely distended ; its outline is usually very 

 indistinct. The pseudopodia are rarely observed. 



4. Pseudodifflugia fascicularis Penard. 

 (Plate LII, figs. 5-8.) 



? Pseudodifflugia amphora 



LEIDY Freshw. Rhiz. N. Amer. (1879), p. 201, pi. xxx, f. 28. 

 Pseudodifflugia fascicularis 



PENARD Faune Rhiz. Leman (1902), pp. 453-455, 5 figs. ; Sarcodines 



in Cat. Invert. Suisse (1905), p. 92. 



AVEEINTZEFP in Trudui S.-Peterb. Obshch. XXXVI, 11 (1906), p. 275. 

 SCHOUTEDEN in Ann. Biol. lacustre, I (1906), p. 364, f. 34. 

 WAILES & PENARD in Proc. R. Irish Acad. XXXI, LXV (1911), p. 19. 

 WAILES in Scott. Natur. 1912, pp. 61, 64 ; in Jm. Linn. Soc., Zool. 



XXXII (1913), pp. 209, 213; in Naturalist, 1913, p. 148. 



Test variable in size, pyriform, yellowish in colour, 

 not compressed, covered with relatively-large quartz- 

 grains, or occasionally diatom-frustules ; aperture 

 circular, terminal, larger in diameter than the neck 

 and surrounded by a collar of variously-sized grains ; 

 nucleus large, containing numerous nucleoles ; plasma 

 limpid, granular, partly filling the test; pseudopodia 

 numerous, long, attenuate, straight or forked. 



Length 23-40 /x; diameter two thirds to three 

 quarters of the length ; aperture about half of the 

 diameter. 



Habitat. Aquatic vegetation. 



ENGLAND. Bedfordshire. 

 SCOTLAND. Outer Hebrides. 



IRELAND. Clare Island and Achill Island, Mayo; 

 Inishbofin, Galway; Kerry. 



British individuals usually vary from 25 to 35 //, in 



