76 BRITISH FRESHWATER RHIZOPODA. 



either touch or are separated from one another (figs. 

 141 a and b). Penard first pointed out that when 

 these tests are disintegrated by acid the residue con- 

 sists of circular discs, the hexagonal appearance being 

 probably due to the cementing material which is 

 soluble in the acid. 



(3) The discs are either circular or oval and are an 

 appreciable distance apart ; they may be all circular 

 or all oval or may be mixed (figs. 142 and 143) ; the 

 cementing material may be homogeneous or consist of 

 two kinds, one more transparent than the other ; the 

 former is quickly dissolved by boiling sulphuric acid, 

 the latter is more resistant but is eventually dissolved, 

 leaving the discs isolated ; this arrangement of discs 

 is described by Wallich (1864). Both circular and 

 oval discs as shown in figs. 143 a and b may be con- 

 nected by these darker bands of cementing material. 



C. truncata F. E. Schulze* may be a form of 0. 

 ampulla, but the neck is very short and rarely has an 

 oblique aperture. 



Var. vitrsea Wailes. (PL XL VI, fig. 2, and fig. 144 



in text.) 



Cyplioderia ampulla var. vitr&ea 

 WAILES & PENARD in Proc. Roy. Irish Acad. XXXI, LXV (1911), 



pp. 27, 28, 29-30, pi. i, ff. 6 a, 6 &. 

 WAILES in Scott. Natur. 1912, pp. 60, 63 ; in Naturalist, 1913, p. 147 ; 



in Murray's Nat. Hist. Bolivia and Peru (1913), pp. 32, 36. 



Test similar in shape to the type but appearing 

 homogeneous and transparent; plasma and pseudo- 

 podia as in the type. 



Length 67-120^, (average 100-1 10 /x); diameter 

 32-50 fjL ; aperture 12-18 /x. 



Habitat. Sphagnum and aquatic vegetation. Rare. 



ENGLAND. Oldstead, K Yorkshire ; Flitwick, Bed- 

 fordshire (/. Saunders, coll.). 



SCOTLAND. Shetlands ; Orkneys. 

 IRELAND. Roonah, Mayo. 



* 'Arch. f. mikr. Anat.,' Bd. xl (1875), pi. v, ff. 21, 22. 



