DIFFLUGIA BACILLIFEBA. 17 



5. Difflugia bacillifera Penard. 

 (Plate XX, fig. 1.) 



Difflugia pyriformis LEIDY (pars) Fresliw. Rhiz. N. Amer. 



'(1879), p. 103, t. x, f. 22. 

 Difflugia bacillifera PENARD in Mem. Soc. Geneve, XXXI 



(1890), 2, p. 146, t. iv, ff. 61-66 ; in Amer. Natur. XX V 



(1893), p. 1079 ; in Arch. Sci. nat. (4) VII (1899), p. 257; 



and Faune Rhiz. Leman (1902), p. 230, ff. 1-4 (p. 231) ; 



RHCJMBLEU in Zeits. wiss. Zool. LXI, 1 (1895), p. 76, t. iv, 



f. 20 ; LEVANDER in Acta Soc. Fauna Fenn. XVIII 



(1900), 6, p. 72 etc. 

 Difflugia pyriformis var. bacillifera LEVANDER in Acta Soc. 



Fauna Fenn. XII (1895), 2, p. 14. 

 Difflugia septenlrionalis var. bacillifera AVERINTZEV in 



Trudui S.-Peterb. Obshch. XXXVI (1906), 2, p. 209. 



(Cf. SCHOUTEDEN in Ann. Biol. Lacustre, I (1906), p. 347.) 



Test variable in form, usually ovoid above, with a 

 rounded semi-circular crown, tapering below into a 

 narrow, often cylindrical neck, and covered wholly or 

 in part with diatom-f rustules intermixed with scattered 

 sand-particles. Nucleus single ; pseudopodia normal. 



Dimensions: Length 145-1 60 p. 



In Sphagnum-pools. Delamere, Cheshire; Tan-y- 

 Bwlch, N. Wales. Moel Siabod, Nant Francon, and 

 above Dolgam, Capel Curig, N. Wales; Calary Bog, 

 Co. Wicklow, Ireland (/. Hopkinson). 



This form is covered always in a greater or less 

 degree with diatoms gathered from the water in which 

 it exists Naviculse, Pinnularix, etc. and by its 

 broadly-rounded crown and tubular neck is readily 

 distinguished from others which have their tests 

 similarly invested. Penard finds in continental ex- 

 amples a further peculiarity, namely, the formation 

 round the mouth of a ring of green particles, resem- 

 bling minute alga3, but we cannot say that we have 

 observed these. It is a variable species, however. In 

 Sphagnum from Capel Curig, gathered by Mr. Hopkin- 

 son in the summer of 1908, examples were found so 



VOL. IT. 2 



