62 BRITISH FRESUWATEIt liHlZOPOUA. 



vary not only in different individuals but even on tlie 

 opposite sides of the same test. The row adjoining 

 the aperture is usually formed of similar plates, but 

 the central series often has a larger or smaller central 

 plate with others arranged aroiind it vaiying in size 

 to suit their positions, but in any case the scales, 

 visible in side view, number four (rarely five) counted 

 in vertical series from the apex to the aperture ; the 

 imbrications of the plates are clearly visible at the 

 margins. 



Usually but few individuals are found in any gather- 

 ing, but occasionally, as at Flitwick, Beds, they may 

 be numerous. The pseudopodia are seldom observed. 

 The neck is never notched as in 8. leuta, from which 

 S. fissirostris is also distinguished by its elongate form 

 and the shape and restricted number of the scales. 



3. Sphenoderia macrolepis Leidy. 

 Plate XLIIT, figs. 11-13.) 



Sphenoderia macrolepis 

 Lbidt Treshw. Ehiz. N". Amer. (1879), p. 232, fig. on p. 290 ; Proc. 



Acad. Philad. 1879, p. 163. 

 Hitchcock Synops. Presliw. Bhiz. (1881), p. 41. 

 Etferth Einfaoh. Lebensf., ed. 3 (1900), p. 268. 

 Pbnabd Faune Rhiz. Leman (1902), p. 577, f. 11, p. 572. 

 AvEEiNTZEFF in Arch. Protist. VIII (1906), p. 113; in Trudui 



S.-Peterb. Obsbob. XXXYI, ii (1906), pp. 301-302. 

 ScHOUTBDEN in Ann. Biol, lacustre, I (1906), pp. 369, 370. 

 Bbown in Jrn, Linn. Soc, Zool. XXXII (1911), pp. 83-84, pi. ix, f . 19 ; 



in Ann. Scott. Nat. Hist. 1911, pp. 229, 231 ; in Scott. Natur. 1913, 



p. 208. 

 "Wailbs & Pbnaed in Proc. B. Irish Acad. XXXI, lxv (1911), pp. 



19, 52-53, pi. vi, f. 32. 

 Wailbs in Scott. Natur. 1912, pp. 61, 64-65 ; in Jrn. Linn. Soc, Zool. 



XXXII (1912), pp. 126, 152. 

 Euglypha macrolepis 



Blochmann Mikr. Thierw. Siisswass. (1886), p. 14; ed. 2 (1895), p. 18. 



Test small, hyaline, oviform, formed of various-sized 

 oval plates and discs ; transverse section oval ; neck 

 conical in side view; aperture linear; nucleus not large, 

 placed posteriorly; plasma clear, colourless, with a vary- 

 ing number of granules ; one contractile vesicle usually 

 present ; pseudopodia few, simple, and radiating. 



