HELEOPERA SYLVATICA. 137 



hyaline discs, or scales of no regular form, their edges 

 showing as a faint reticulation ; the crown smooth or 

 capped with a few adhering sand-grains. The test in 

 narrow lateral view compressed to about half the 

 width, and narrowed anteriorly, the mouth forming a 

 notch. Plasma, nucleus, and pseudopodia as in H. 

 petricola. 



Dimensions : Length 50-75 //, ; breadth 25-30 /x. 



In Sphagnum, not common. Dunham, Cheshire ; 

 Tan-y-Bwlch, N. Wales. Moel Siabod, N. Wales, at 

 2500 feet (J. Hopkinson). 



This form, which we have in past years found in 

 considerable abundance, at Dunham, corresponds in 

 outline, and particularly in the structure of the mouth, 

 with Penard's figure in ' Faune Rhiz. Leman.' That 

 figure represents the test as covered with minute 

 circular discs ; ours have, in place of these, amorphous 

 scales ; and while the crown of the test is naked in the 

 Swiss examples, ours are furnished less abundantly, 

 however, than in H. petricola with a not very large 

 allowance of sand-grains. It is curious to observe 

 that, according to the author cited, this elegant species 

 occurs in mosses of woods and hedge banks " never 

 in Sphagnum." Our examples are from Sphagnum 

 solely. Some, especially those which are encysted, are 

 beautifully transparent, and their elegance of form at 

 once arrests attention. 



2. Heleopera petricola Leidy. 

 (Plate XXIX, figs. 13-19.) 



Heleopera pelricula LKIDY (pars) Fresh w. Rhiz. N. Araer. 

 (1879), p. 165, t. xxvi, ff. 12-15 ; in Pr. Acad. Philad. 

 1879, p. 162, and op. cit. 1880, pp. 335, 338; HITCHCOCK 

 Synops. Freshw. Rhiz. (1881), p. 24 ; TAKANEK in 

 Sitzber. bohm. Ges. Wiss. 1881 (1882), p. 232; and in 

 Abh.bohm. Ges. Wiss. (6) XI (1882), 8, p. 42, t. iv, ff. 9- 

 15; BLOCHMANN Mikr. Thierw. Stisswass. (1886), p. 13, 

 t. i, f. 27 ; and ed. 2 (1895), p. 17; PENARD in Mem. Soc. 

 Geneve, XXXI (1890), 2, p. 167, t. vii, ff. 56-58; Faune 



